android_webview/browser/browser_view_renderer.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "android_webview/browser/browser_view_renderer.h"
   6
   7 #include "android_webview/browser/browser_view_renderer_client.h"
   8 #include "android_webview/browser/child_frame.h"
   9 #include "base/auto_reset.h"
  10 #include "base/command_line.h"
  11 #include "base/logging.h"
  12 #include "base/strings/string_number_conversions.h"
  13 #include "base/strings/stringprintf.h"
  14 #include "base/supports_user_data.h"
  15 #include "base/trace_event/trace_event_argument.h"
  16 #include "cc/output/compositor_frame.h"
  17 #include "content/public/browser/web_contents.h"
  18 #include "content/public/common/content_switches.h"
  19 #include "gpu/command_buffer/service/gpu_switches.h"
  20 #include "third_party/skia/include/core/SkBitmap.h"
  21 #include "third_party/skia/include/core/SkCanvas.h"
  22 #include "third_party/skia/include/core/SkPicture.h"
  23 #include "third_party/skia/include/core/SkPictureRecorder.h"
  24 #include "ui/gfx/geometry/vector2d_conversions.h"
  25
  26 namespace android_webview {
  27
  28 namespace {
  29
  30 const double kEpsilon = 1e-8;
  31
  32 const int64 kFallbackTickTimeoutInMilliseconds = 100;
  33
  34 // Used to calculate memory allocation. Determined experimentally.
  35 const size_t kMemoryMultiplier = 20;
  36 const size_t kBytesPerPixel = 4;
  37 const size_t kMemoryAllocationStep = 5 * 1024 * 1024;
  38 uint64 g_memory_override_in_bytes = 0u;
  39
  40 const void* kBrowserViewRendererUserDataKey = &kBrowserViewRendererUserDataKey;
  41
  42 class BrowserViewRendererUserData : public base::SupportsUserData::Data {
  43  public:
  44   BrowserViewRendererUserData(BrowserViewRenderer* ptr) : bvr_(ptr) {}
  45
  46   static BrowserViewRenderer* GetBrowserViewRenderer(
  47       content::WebContents* web_contents) {
  48     if (!web_contents)
  49       return NULL;
  50     BrowserViewRendererUserData* data =
  51         static_cast<BrowserViewRendererUserData*>(
  52             web_contents->GetUserData(kBrowserViewRendererUserDataKey));
  53     return data ? data->bvr_ : NULL;
  54   }
  55
  56  private:
  57   BrowserViewRenderer* bvr_;
  58 };
  59
  60 }  // namespace
  61
  62 // static
  63 void BrowserViewRenderer::CalculateTileMemoryPolicy() {
  64   base::CommandLine* cl = base::CommandLine::ForCurrentProcess();
  65
  66   // If the value was overridden on the command line, use the specified value.
  67   bool client_hard_limit_bytes_overridden =
  68       cl->HasSwitch(switches::kForceGpuMemAvailableMb);
  69   if (client_hard_limit_bytes_overridden) {
  70     base::StringToUint64(
  71         base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
  72             switches::kForceGpuMemAvailableMb),
  73         &g_memory_override_in_bytes);
  74     g_memory_override_in_bytes *= 1024 * 1024;
  75   }
  76 }
  77
  78 // static
  79 BrowserViewRenderer* BrowserViewRenderer::FromWebContents(
  80     content::WebContents* web_contents) {
  81   return BrowserViewRendererUserData::GetBrowserViewRenderer(web_contents);
  82 }
  83
  84 BrowserViewRenderer::BrowserViewRenderer(
  85     BrowserViewRendererClient* client,
  86     const scoped_refptr<base::SingleThreadTaskRunner>& ui_task_runner)
  87     : client_(client),
  88       shared_renderer_state_(ui_task_runner, this),
  89       ui_task_runner_(ui_task_runner),
  90       compositor_(NULL),
  91       is_paused_(false),
  92       view_visible_(false),
  93       window_visible_(false),
  94       attached_to_window_(false),
  95       hardware_enabled_(false),
  96       dip_scale_(0.0),
  97       page_scale_factor_(1.0),
  98       on_new_picture_enable_(false),
  99       clear_view_(false),
 100       offscreen_pre_raster_(false),
 101       fallback_tick_pending_(false) {
 102 }
 103
 104 BrowserViewRenderer::~BrowserViewRenderer() {
 105 }
 106
 107 void BrowserViewRenderer::RegisterWithWebContents(
 108     content::WebContents* web_contents) {
 109   web_contents->SetUserData(kBrowserViewRendererUserDataKey,
 110                             new BrowserViewRendererUserData(this));
 111 }
 112
 113 SharedRendererState* BrowserViewRenderer::GetAwDrawGLViewContext() {
 114   return &shared_renderer_state_;
 115 }
 116
 117 bool BrowserViewRenderer::RequestDrawGL(bool wait_for_completion) {
 118   return client_->RequestDrawGL(wait_for_completion);
 119 }
 120
 121 void BrowserViewRenderer::TrimMemory(const int level, const bool visible) {
 122   DCHECK(ui_task_runner_->BelongsToCurrentThread());
 123   // Constants from Android ComponentCallbacks2.
 124   enum {
 125     TRIM_MEMORY_RUNNING_LOW = 10,
 126     TRIM_MEMORY_UI_HIDDEN = 20,
 127     TRIM_MEMORY_BACKGROUND = 40,
 128     TRIM_MEMORY_MODERATE = 60,
 129   };
 130
 131   // Not urgent enough. TRIM_MEMORY_UI_HIDDEN is treated specially because
 132   // it does not indicate memory pressure, but merely that the app is
 133   // backgrounded.
 134   if (level < TRIM_MEMORY_RUNNING_LOW || level == TRIM_MEMORY_UI_HIDDEN)
 135     return;
 136
 137   // Do not release resources on view we expect to get DrawGL soon.
 138   if (level < TRIM_MEMORY_BACKGROUND && visible)
 139     return;
 140
 141   // Nothing to drop.
 142   if (!compositor_ || !hardware_enabled_)
 143     return;
 144
 145   TRACE_EVENT0("android_webview", "BrowserViewRenderer::TrimMemory");
 146
 147   // If offscreen pre-raster is disabled, drop everything in hardware. Otherwise
 148   // keep the tiles and just delete the HardwareRenderer.
 149   if (level >= TRIM_MEMORY_MODERATE) {
 150     if (offscreen_pre_raster_)
 151       shared_renderer_state_.DeleteHardwareRendererOnUI();
 152     else
 153       shared_renderer_state_.ReleaseHardwareDrawIfNeededOnUI();
 154     return;
 155   }
 156
 157   // Just set the memory limit to 0 and drop all tiles. This will be reset to
 158   // normal levels in the next DrawGL call.
 159   if (!offscreen_pre_raster_)
 160     compositor_->SetMemoryPolicy(0u);
 161 }
 162
 163 void BrowserViewRenderer::UpdateMemoryPolicy() {
 164   if (!hardware_enabled_) {
 165     compositor_->SetMemoryPolicy(0u);
 166     return;
 167   }
 168
 169   size_t bytes_limit = 0u;
 170   if (g_memory_override_in_bytes) {
 171     bytes_limit = static_cast<size_t>(g_memory_override_in_bytes);
 172   } else {
 173     ParentCompositorDrawConstraints parent_draw_constraints =
 174         shared_renderer_state_.GetParentDrawConstraintsOnUI();
 175     gfx::Rect interest_rect =
 176         offscreen_pre_raster_ || parent_draw_constraints.is_layer
 177             ? gfx::Rect(size_)
 178             : last_on_draw_global_visible_rect_;
 179     size_t width = interest_rect.width();
 180     size_t height = interest_rect.height();
 181     bytes_limit = kMemoryMultiplier * kBytesPerPixel * width * height;
 182     // Round up to a multiple of kMemoryAllocationStep.
 183     bytes_limit =
 184         (bytes_limit / kMemoryAllocationStep + 1) * kMemoryAllocationStep;
 185   }
 186
 187   compositor_->SetMemoryPolicy(bytes_limit);
 188 }
 189
 190 void BrowserViewRenderer::PrepareToDraw(const gfx::Vector2d& scroll,
 191                                         const gfx::Rect& global_visible_rect) {
 192   last_on_draw_scroll_offset_ = scroll;
 193   last_on_draw_global_visible_rect_ = global_visible_rect;
 194 }
 195
 196 bool BrowserViewRenderer::CanOnDraw() {
 197   if (!compositor_) {
 198     TRACE_EVENT_INSTANT0("android_webview", "EarlyOut_NoCompositor",
 199                          TRACE_EVENT_SCOPE_THREAD);
 200     return false;
 201   }
 202   if (clear_view_) {
 203     TRACE_EVENT_INSTANT0("android_webview", "EarlyOut_ClearView",
 204                          TRACE_EVENT_SCOPE_THREAD);
 205     return false;
 206   }
 207
 208   return true;
 209 }
 210
 211 bool BrowserViewRenderer::OnDrawHardware() {
 212   TRACE_EVENT0("android_webview", "BrowserViewRenderer::OnDrawHardware");
 213
 214   shared_renderer_state_.InitializeHardwareDrawIfNeededOnUI();
 215
 216   if (!CanOnDraw()) {
 217     return false;
 218   }
 219
 220   shared_renderer_state_.SetScrollOffsetOnUI(last_on_draw_scroll_offset_);
 221   hardware_enabled_ = true;
 222
 223   return CompositeHw();
 224 }
 225
 226 bool BrowserViewRenderer::CompositeHw() {
 227   CancelFallbackTick();
 228
 229   ReturnResourceFromParent();
 230   UpdateMemoryPolicy();
 231
 232   ParentCompositorDrawConstraints parent_draw_constraints =
 233       shared_renderer_state_.GetParentDrawConstraintsOnUI();
 234   gfx::Size surface_size(size_);
 235   gfx::Rect viewport(surface_size);
 236   gfx::Rect clip = viewport;
 237   gfx::Transform transform_for_tile_priority =
 238       parent_draw_constraints.transform;
 239
 240   // If the WebView is on a layer, WebView does not know what transform is
 241   // applied onto the layer so global visible rect does not make sense here.
 242   // In this case, just use the surface rect for tiling.
 243   gfx::Rect viewport_rect_for_tile_priority;
 244
 245   // Leave viewport_rect_for_tile_priority empty if offscreen_pre_raster_ is on.
 246   if (!offscreen_pre_raster_ && !parent_draw_constraints.is_layer) {
 247     viewport_rect_for_tile_priority = last_on_draw_global_visible_rect_;
 248   }
 249
 250   scoped_ptr<cc::CompositorFrame> frame =
 251       compositor_->DemandDrawHw(surface_size,
 252                                 gfx::Transform(),
 253                                 viewport,
 254                                 clip,
 255                                 viewport_rect_for_tile_priority,
 256                                 transform_for_tile_priority);
 257   if (!frame.get()) {
 258     TRACE_EVENT_INSTANT0("android_webview", "NoNewFrame",
 259                          TRACE_EVENT_SCOPE_THREAD);
 260     return false;
 261   }
 262
 263   scoped_ptr<ChildFrame> child_frame = make_scoped_ptr(
 264       new ChildFrame(frame.Pass(), viewport_rect_for_tile_priority.IsEmpty(),
 265                      transform_for_tile_priority, offscreen_pre_raster_,
 266                      parent_draw_constraints.is_layer));
 267
 268   // Uncommitted frame can happen with consecutive fallback ticks.
 269   ReturnUnusedResource(shared_renderer_state_.PassUncommittedFrameOnUI());
 270   shared_renderer_state_.SetCompositorFrameOnUI(child_frame.Pass());
 271   return true;
 272 }
 273
 274 void BrowserViewRenderer::UpdateParentDrawConstraints() {
 275   PostInvalidateWithFallback();
 276   ParentCompositorDrawConstraints parent_draw_constraints =
 277       shared_renderer_state_.GetParentDrawConstraintsOnUI();
 278   client_->ParentDrawConstraintsUpdated(parent_draw_constraints);
 279 }
 280
 281 void BrowserViewRenderer::ReturnUnusedResource(
 282     scoped_ptr<ChildFrame> child_frame) {
 283   if (!child_frame.get() || !child_frame->frame.get())
 284     return;
 285
 286   cc::CompositorFrameAck frame_ack;
 287   cc::TransferableResource::ReturnResources(
 288       child_frame->frame->delegated_frame_data->resource_list,
 289       &frame_ack.resources);
 290   if (compositor_ && !frame_ack.resources.empty())
 291     compositor_->ReturnResources(frame_ack);
 292 }
 293
 294 void BrowserViewRenderer::ReturnResourceFromParent() {
 295   cc::CompositorFrameAck frame_ack;
 296   shared_renderer_state_.SwapReturnedResourcesOnUI(&frame_ack.resources);
 297   if (compositor_ && !frame_ack.resources.empty()) {
 298     compositor_->ReturnResources(frame_ack);
 299   }
 300 }
 301
 302 void BrowserViewRenderer::DetachFunctorFromView() {
 303   client_->DetachFunctorFromView();
 304 }
 305
 306 bool BrowserViewRenderer::OnDrawSoftware(SkCanvas* canvas) {
 307   return CanOnDraw() && CompositeSW(canvas);
 308 }
 309
 310 skia::RefPtr<SkPicture> BrowserViewRenderer::CapturePicture(int width,
 311                                                             int height) {
 312   TRACE_EVENT0("android_webview", "BrowserViewRenderer::CapturePicture");
 313
 314   // Return empty Picture objects for empty SkPictures.
 315   if (width <= 0 || height <= 0) {
 316     SkPictureRecorder emptyRecorder;
 317     emptyRecorder.beginRecording(0, 0);
 318     return skia::AdoptRef(emptyRecorder.endRecording());
 319   }
 320
 321   // Reset scroll back to the origin, will go back to the old
 322   // value when scroll_reset is out of scope.
 323   base::AutoReset<gfx::Vector2dF> scroll_reset(&scroll_offset_dip_,
 324                                                gfx::Vector2dF());
 325
 326   SkPictureRecorder recorder;
 327   SkCanvas* rec_canvas = recorder.beginRecording(width, height, NULL, 0);
 328   if (compositor_)
 329     CompositeSW(rec_canvas);
 330   return skia::AdoptRef(recorder.endRecording());
 331 }
 332
 333 void BrowserViewRenderer::EnableOnNewPicture(bool enabled) {
 334   on_new_picture_enable_ = enabled;
 335 }
 336
 337 void BrowserViewRenderer::ClearView() {
 338   TRACE_EVENT_INSTANT0("android_webview",
 339                        "BrowserViewRenderer::ClearView",
 340                        TRACE_EVENT_SCOPE_THREAD);
 341   if (clear_view_)
 342     return;
 343
 344   clear_view_ = true;
 345   // Always invalidate ignoring the compositor to actually clear the webview.
 346   PostInvalidateWithFallback();
 347 }
 348
 349 void BrowserViewRenderer::SetOffscreenPreRaster(bool enable) {
 350   if (offscreen_pre_raster_ != enable && compositor_)
 351     UpdateMemoryPolicy();
 352
 353   offscreen_pre_raster_ = enable;
 354 }
 355
 356 void BrowserViewRenderer::SetIsPaused(bool paused) {
 357   TRACE_EVENT_INSTANT1("android_webview",
 358                        "BrowserViewRenderer::SetIsPaused",
 359                        TRACE_EVENT_SCOPE_THREAD,
 360                        "paused",
 361                        paused);
 362   is_paused_ = paused;
 363   UpdateCompositorIsActive();
 364 }
 365
 366 void BrowserViewRenderer::SetViewVisibility(bool view_visible) {
 367   TRACE_EVENT_INSTANT1("android_webview",
 368                        "BrowserViewRenderer::SetViewVisibility",
 369                        TRACE_EVENT_SCOPE_THREAD,
 370                        "view_visible",
 371                        view_visible);
 372   view_visible_ = view_visible;
 373 }
 374
 375 void BrowserViewRenderer::SetWindowVisibility(bool window_visible) {
 376   TRACE_EVENT_INSTANT1("android_webview",
 377                        "BrowserViewRenderer::SetWindowVisibility",
 378                        TRACE_EVENT_SCOPE_THREAD,
 379                        "window_visible",
 380                        window_visible);
 381   window_visible_ = window_visible;
 382   UpdateCompositorIsActive();
 383 }
 384
 385 void BrowserViewRenderer::OnSizeChanged(int width, int height) {
 386   TRACE_EVENT_INSTANT2("android_webview",
 387                        "BrowserViewRenderer::OnSizeChanged",
 388                        TRACE_EVENT_SCOPE_THREAD,
 389                        "width",
 390                        width,
 391                        "height",
 392                        height);
 393   size_.SetSize(width, height);
 394 }
 395
 396 void BrowserViewRenderer::OnAttachedToWindow(int width, int height) {
 397   TRACE_EVENT2("android_webview",
 398                "BrowserViewRenderer::OnAttachedToWindow",
 399                "width",
 400                width,
 401                "height",
 402                height);
 403   attached_to_window_ = true;
 404   size_.SetSize(width, height);
 405   UpdateCompositorIsActive();
 406 }
 407
 408 void BrowserViewRenderer::OnDetachedFromWindow() {
 409   TRACE_EVENT0("android_webview", "BrowserViewRenderer::OnDetachedFromWindow");
 410   shared_renderer_state_.ReleaseHardwareDrawIfNeededOnUI();
 411   attached_to_window_ = false;
 412   DCHECK(!hardware_enabled_);
 413   UpdateCompositorIsActive();
 414 }
 415
 416 void BrowserViewRenderer::OnComputeScroll(base::TimeTicks animation_time) {
 417   if (pending_fling_animation_.is_null())
 418     return;
 419   TRACE_EVENT0("android_webview", "BrowserViewRenderer::OnComputeScroll");
 420   DCHECK(!pending_fling_animation_.is_null());
 421   AnimationCallback animation = pending_fling_animation_;
 422   pending_fling_animation_.Reset();
 423   animation.Run(animation_time);
 424 }
 425
 426 void BrowserViewRenderer::ReleaseHardware() {
 427   DCHECK(hardware_enabled_);
 428   ReturnUnusedResource(shared_renderer_state_.PassUncommittedFrameOnUI());
 429   ReturnResourceFromParent();
 430   DCHECK(shared_renderer_state_.ReturnedResourcesEmptyOnUI());
 431
 432   if (compositor_) {
 433     compositor_->SetMemoryPolicy(0u);
 434   }
 435
 436   hardware_enabled_ = false;
 437 }
 438
 439 bool BrowserViewRenderer::IsVisible() const {
 440   // Ignore |window_visible_| if |attached_to_window_| is false.
 441   return view_visible_ && (!attached_to_window_ || window_visible_);
 442 }
 443
 444 gfx::Rect BrowserViewRenderer::GetScreenRect() const {
 445   return gfx::Rect(client_->GetLocationOnScreen(), size_);
 446 }
 447
 448 void BrowserViewRenderer::DidInitializeCompositor(
 449     content::SynchronousCompositor* compositor) {
 450   TRACE_EVENT0("android_webview",
 451                "BrowserViewRenderer::DidInitializeCompositor");
 452   DCHECK(compositor);
 453   DCHECK(!compositor_);
 454   compositor_ = compositor;
 455   UpdateCompositorIsActive();
 456 }
 457
 458 void BrowserViewRenderer::DidDestroyCompositor(
 459     content::SynchronousCompositor* compositor) {
 460   TRACE_EVENT0("android_webview", "BrowserViewRenderer::DidDestroyCompositor");
 461   DCHECK(compositor_);
 462   compositor_->SetIsActive(false);
 463   compositor_ = NULL;
 464 }
 465
 466 void BrowserViewRenderer::SetDipScale(float dip_scale) {
 467   dip_scale_ = dip_scale;
 468   CHECK_GT(dip_scale_, 0.f);
 469 }
 470
 471 gfx::Vector2d BrowserViewRenderer::max_scroll_offset() const {
 472   DCHECK_GT(dip_scale_, 0.f);
 473   return gfx::ToCeiledVector2d(gfx::ScaleVector2d(
 474       max_scroll_offset_dip_, dip_scale_ * page_scale_factor_));
 475 }
 476
 477 void BrowserViewRenderer::ScrollTo(gfx::Vector2d scroll_offset) {
 478   gfx::Vector2d max_offset = max_scroll_offset();
 479   gfx::Vector2dF scroll_offset_dip;
 480   // To preserve the invariant that scrolling to the maximum physical pixel
 481   // value also scrolls to the maximum dip pixel value we transform the physical
 482   // offset into the dip offset by using a proportion (instead of dividing by
 483   // dip_scale * page_scale_factor).
 484   if (max_offset.x()) {
 485     scroll_offset_dip.set_x((scroll_offset.x() * max_scroll_offset_dip_.x()) /
 486                             max_offset.x());
 487   }
 488   if (max_offset.y()) {
 489     scroll_offset_dip.set_y((scroll_offset.y() * max_scroll_offset_dip_.y()) /
 490                             max_offset.y());
 491   }
 492
 493   DCHECK_LE(0.f, scroll_offset_dip.x());
 494   DCHECK_LE(0.f, scroll_offset_dip.y());
 495   DCHECK(scroll_offset_dip.x() < max_scroll_offset_dip_.x() ||
 496          scroll_offset_dip.x() - max_scroll_offset_dip_.x() < kEpsilon)
 497       << scroll_offset_dip.x() << " " << max_scroll_offset_dip_.x();
 498   DCHECK(scroll_offset_dip.y() < max_scroll_offset_dip_.y() ||
 499          scroll_offset_dip.y() - max_scroll_offset_dip_.y() < kEpsilon)
 500       << scroll_offset_dip.y() << " " << max_scroll_offset_dip_.y();
 501
 502   if (scroll_offset_dip_ == scroll_offset_dip)
 503     return;
 504
 505   scroll_offset_dip_ = scroll_offset_dip;
 506
 507   TRACE_EVENT_INSTANT2("android_webview",
 508                "BrowserViewRenderer::ScrollTo",
 509                TRACE_EVENT_SCOPE_THREAD,
 510                "x",
 511                scroll_offset_dip.x(),
 512                "y",
 513                scroll_offset_dip.y());
 514
 515   if (compositor_)
 516     compositor_->DidChangeRootLayerScrollOffset();
 517 }
 518
 519 void BrowserViewRenderer::DidUpdateContent() {
 520   TRACE_EVENT_INSTANT0("android_webview",
 521                        "BrowserViewRenderer::DidUpdateContent",
 522                        TRACE_EVENT_SCOPE_THREAD);
 523   clear_view_ = false;
 524   if (on_new_picture_enable_)
 525     client_->OnNewPicture();
 526 }
 527
 528 void BrowserViewRenderer::SetTotalRootLayerScrollOffset(
 529     gfx::Vector2dF scroll_offset_dip) {
 530   // TOOD(mkosiba): Add a DCHECK to say that this does _not_ get called during
 531   // DrawGl when http://crbug.com/249972 is fixed.
 532   if (scroll_offset_dip_ == scroll_offset_dip)
 533     return;
 534
 535   scroll_offset_dip_ = scroll_offset_dip;
 536
 537   gfx::Vector2d max_offset = max_scroll_offset();
 538   gfx::Vector2d scroll_offset;
 539   // For an explanation as to why this is done this way see the comment in
 540   // BrowserViewRenderer::ScrollTo.
 541   if (max_scroll_offset_dip_.x()) {
 542     scroll_offset.set_x((scroll_offset_dip.x() * max_offset.x()) /
 543                         max_scroll_offset_dip_.x());
 544   }
 545
 546   if (max_scroll_offset_dip_.y()) {
 547     scroll_offset.set_y((scroll_offset_dip.y() * max_offset.y()) /
 548                         max_scroll_offset_dip_.y());
 549   }
 550
 551   DCHECK_LE(0, scroll_offset.x());
 552   DCHECK_LE(0, scroll_offset.y());
 553   DCHECK_LE(scroll_offset.x(), max_offset.x());
 554   DCHECK_LE(scroll_offset.y(), max_offset.y());
 555
 556   client_->ScrollContainerViewTo(scroll_offset);
 557 }
 558
 559 gfx::Vector2dF BrowserViewRenderer::GetTotalRootLayerScrollOffset() {
 560   return scroll_offset_dip_;
 561 }
 562
 563 bool BrowserViewRenderer::IsExternalScrollActive() const {
 564   return client_->IsSmoothScrollingActive();
 565 }
 566
 567 void BrowserViewRenderer::UpdateRootLayerState(
 568     const gfx::Vector2dF& total_scroll_offset_dip,
 569     const gfx::Vector2dF& max_scroll_offset_dip,
 570     const gfx::SizeF& scrollable_size_dip,
 571     float page_scale_factor,
 572     float min_page_scale_factor,
 573     float max_page_scale_factor) {
 574   TRACE_EVENT_INSTANT1(
 575       "android_webview",
 576       "BrowserViewRenderer::UpdateRootLayerState",
 577       TRACE_EVENT_SCOPE_THREAD,
 578       "state",
 579       RootLayerStateAsValue(total_scroll_offset_dip, scrollable_size_dip));
 580
 581   DCHECK_GT(dip_scale_, 0.f);
 582
 583   max_scroll_offset_dip_ = max_scroll_offset_dip;
 584   DCHECK_LE(0.f, max_scroll_offset_dip_.x());
 585   DCHECK_LE(0.f, max_scroll_offset_dip_.y());
 586
 587   page_scale_factor_ = page_scale_factor;
 588   DCHECK_GT(page_scale_factor_, 0.f);
 589
 590   client_->UpdateScrollState(max_scroll_offset(),
 591                              scrollable_size_dip,
 592                              page_scale_factor,
 593                              min_page_scale_factor,
 594                              max_page_scale_factor);
 595   SetTotalRootLayerScrollOffset(total_scroll_offset_dip);
 596 }
 597
 598 scoped_refptr<base::trace_event::ConvertableToTraceFormat>
 599 BrowserViewRenderer::RootLayerStateAsValue(
 600     const gfx::Vector2dF& total_scroll_offset_dip,
 601     const gfx::SizeF& scrollable_size_dip) {
 602   scoped_refptr<base::trace_event::TracedValue> state =
 603       new base::trace_event::TracedValue();
 604
 605   state->SetDouble("total_scroll_offset_dip.x", total_scroll_offset_dip.x());
 606   state->SetDouble("total_scroll_offset_dip.y", total_scroll_offset_dip.y());
 607
 608   state->SetDouble("max_scroll_offset_dip.x", max_scroll_offset_dip_.x());
 609   state->SetDouble("max_scroll_offset_dip.y", max_scroll_offset_dip_.y());
 610
 611   state->SetDouble("scrollable_size_dip.width", scrollable_size_dip.width());
 612   state->SetDouble("scrollable_size_dip.height", scrollable_size_dip.height());
 613
 614   state->SetDouble("page_scale_factor", page_scale_factor_);
 615   return state;
 616 }
 617
 618 void BrowserViewRenderer::SetNeedsAnimateScroll(
 619     const AnimationCallback& scroll_animation) {
 620   pending_fling_animation_ = scroll_animation;
 621   // No need to reschedule the fallback tick here because the compositor is
 622   // fine with the animation not being ticked. The invalidate could happen some
 623   // time later, or not at all.
 624   client_->PostInvalidate();
 625 }
 626
 627 void BrowserViewRenderer::DidOverscroll(gfx::Vector2dF accumulated_overscroll,
 628                                         gfx::Vector2dF latest_overscroll_delta,
 629                                         gfx::Vector2dF current_fling_velocity) {
 630   const float physical_pixel_scale = dip_scale_ * page_scale_factor_;
 631   if (accumulated_overscroll == latest_overscroll_delta)
 632     overscroll_rounding_error_ = gfx::Vector2dF();
 633   gfx::Vector2dF scaled_overscroll_delta =
 634       gfx::ScaleVector2d(latest_overscroll_delta, physical_pixel_scale);
 635   gfx::Vector2d rounded_overscroll_delta = gfx::ToRoundedVector2d(
 636       scaled_overscroll_delta + overscroll_rounding_error_);
 637   overscroll_rounding_error_ =
 638       scaled_overscroll_delta - rounded_overscroll_delta;
 639   gfx::Vector2dF fling_velocity_pixels =
 640       gfx::ScaleVector2d(current_fling_velocity, physical_pixel_scale);
 641
 642   client_->DidOverscroll(rounded_overscroll_delta, fling_velocity_pixels);
 643 }
 644
 645 void BrowserViewRenderer::PostInvalidate() {
 646   TRACE_EVENT_INSTANT0("android_webview", "BrowserViewRenderer::PostInvalidate",
 647                        TRACE_EVENT_SCOPE_THREAD);
 648   PostInvalidateWithFallback();
 649 }
 650
 651 void BrowserViewRenderer::PostInvalidateWithFallback() {
 652   // Always call view invalidate. We rely the Android framework to ignore the
 653   // invalidate when it's not needed such as when view is not visible.
 654   client_->PostInvalidate();
 655
 656   // Stop fallback ticks when one of these is true.
 657   // 1) Webview is paused. Also need to check we are not in clear view since
 658   // paused, offscreen still expect clear view to recover.
 659   // 2) If we are attached to window and the window is not visible (eg when
 660   // app is in the background). We are sure in this case the webview is used
 661   // "on-screen" but that updates are not needed when in the background.
 662   bool throttle_fallback_tick =
 663       (is_paused_ && !clear_view_) || (attached_to_window_ && !window_visible_);
 664
 665   if (throttle_fallback_tick || fallback_tick_pending_)
 666     return;
 667
 668   DCHECK(post_fallback_tick_.IsCancelled());
 669   DCHECK(fallback_tick_fired_.IsCancelled());
 670
 671   post_fallback_tick_.Reset(base::Bind(&BrowserViewRenderer::PostFallbackTick,
 672                                        base::Unretained(this)));
 673   ui_task_runner_->PostTask(FROM_HERE, post_fallback_tick_.callback());
 674   fallback_tick_pending_ = true;
 675 }
 676
 677 void BrowserViewRenderer::CancelFallbackTick() {
 678   post_fallback_tick_.Cancel();
 679   fallback_tick_fired_.Cancel();
 680   fallback_tick_pending_ = false;
 681 }
 682
 683 void BrowserViewRenderer::PostFallbackTick() {
 684   DCHECK(fallback_tick_fired_.IsCancelled());
 685   TRACE_EVENT0("android_webview", "BrowserViewRenderer::PostFallbackTick");
 686   post_fallback_tick_.Cancel();
 687   fallback_tick_fired_.Reset(base::Bind(&BrowserViewRenderer::FallbackTickFired,
 688                                         base::Unretained(this)));
 689   ui_task_runner_->PostDelayedTask(
 690       FROM_HERE, fallback_tick_fired_.callback(),
 691       base::TimeDelta::FromMilliseconds(kFallbackTickTimeoutInMilliseconds));
 692 }
 693
 694 void BrowserViewRenderer::FallbackTickFired() {
 695   TRACE_EVENT0("android_webview", "BrowserViewRenderer::FallbackTickFired");
 696   // This should only be called if OnDraw or DrawGL did not come in time, which
 697   // means fallback_tick_pending_ must still be true.
 698   DCHECK(fallback_tick_pending_);
 699   fallback_tick_fired_.Cancel();
 700   fallback_tick_pending_ = false;
 701   if (compositor_) {
 702     if (hardware_enabled_) {
 703       CompositeHw();
 704     } else {
 705       ForceFakeCompositeSW();
 706     }
 707   }
 708 }
 709
 710 void BrowserViewRenderer::ForceFakeCompositeSW() {
 711   DCHECK(compositor_);
 712   SkBitmap bitmap;
 713   bitmap.allocN32Pixels(1, 1);
 714   bitmap.eraseColor(0);
 715   SkCanvas canvas(bitmap);
 716   CompositeSW(&canvas);
 717 }
 718
 719 bool BrowserViewRenderer::CompositeSW(SkCanvas* canvas) {
 720   DCHECK(compositor_);
 721   CancelFallbackTick();
 722   ReturnResourceFromParent();
 723   return compositor_->DemandDrawSw(canvas);
 724 }
 725
 726 void BrowserViewRenderer::UpdateCompositorIsActive() {
 727   if (compositor_)
 728     compositor_->SetIsActive(!is_paused_ &&
 729                              (!attached_to_window_ || window_visible_));
 730 }
 731
 732 std::string BrowserViewRenderer::ToString() const {
 733   std::string str;
 734   base::StringAppendF(&str, "is_paused: %d ", is_paused_);
 735   base::StringAppendF(&str, "view_visible: %d ", view_visible_);
 736   base::StringAppendF(&str, "window_visible: %d ", window_visible_);
 737   base::StringAppendF(&str, "dip_scale: %f ", dip_scale_);
 738   base::StringAppendF(&str, "page_scale_factor: %f ", page_scale_factor_);
 739   base::StringAppendF(&str, "fallback_tick_pending: %d ",
 740                       fallback_tick_pending_);
 741   base::StringAppendF(&str, "view size: %s ", size_.ToString().c_str());
 742   base::StringAppendF(&str, "attached_to_window: %d ", attached_to_window_);
 743   base::StringAppendF(&str,
 744                       "global visible rect: %s ",
 745                       last_on_draw_global_visible_rect_.ToString().c_str());
 746   base::StringAppendF(
 747       &str, "scroll_offset_dip: %s ", scroll_offset_dip_.ToString().c_str());
 748   base::StringAppendF(&str,
 749                       "overscroll_rounding_error_: %s ",
 750                       overscroll_rounding_error_.ToString().c_str());
 751   base::StringAppendF(
 752       &str, "on_new_picture_enable: %d ", on_new_picture_enable_);
 753   base::StringAppendF(&str, "clear_view: %d ", clear_view_);
 754   return str;
 755 }
 756
 757 }  // namespace android_webview