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 // This function updates the resource allocation in GlobalTileManager.
 122 void BrowserViewRenderer::TrimMemory(const int level, const bool visible) {
 123   DCHECK(ui_task_runner_->BelongsToCurrentThread());
 124   // Constants from Android ComponentCallbacks2.
 125   enum {
 126     TRIM_MEMORY_RUNNING_LOW = 10,
 127     TRIM_MEMORY_UI_HIDDEN = 20,
 128     TRIM_MEMORY_BACKGROUND = 40,
 129     TRIM_MEMORY_MODERATE = 60,
 130   };
 131
 132   // Not urgent enough. TRIM_MEMORY_UI_HIDDEN is treated specially because
 133   // it does not indicate memory pressure, but merely that the app is
 134   // backgrounded.
 135   if (level < TRIM_MEMORY_RUNNING_LOW || level == TRIM_MEMORY_UI_HIDDEN)
 136     return;
 137
 138   // Do not release resources on view we expect to get DrawGL soon.
 139   if (level < TRIM_MEMORY_BACKGROUND && visible)
 140     return;
 141
 142   // Nothing to drop.
 143   if (!compositor_ || !hardware_enabled_)
 144     return;
 145
 146   TRACE_EVENT0("android_webview", "BrowserViewRenderer::TrimMemory");
 147
 148   // Drop everything in hardware.
 149   if (level >= TRIM_MEMORY_MODERATE) {
 150     shared_renderer_state_.ReleaseHardwareDrawIfNeededOnUI();
 151     return;
 152   }
 153
 154   // Just set the memory limit to 0 and drop all tiles. This will be reset to
 155   // normal levels in the next DrawGL call.
 156   compositor_->SetMemoryPolicy(0u);
 157   ForceFakeCompositeSW();
 158 }
 159
 160 size_t BrowserViewRenderer::CalculateDesiredMemoryPolicy() {
 161   if (g_memory_override_in_bytes)
 162     return static_cast<size_t>(g_memory_override_in_bytes);
 163
 164   gfx::Rect interest_rect = offscreen_pre_raster_
 165                                 ? gfx::Rect(size_)
 166                                 : last_on_draw_global_visible_rect_;
 167   size_t width = interest_rect.width();
 168   size_t height = interest_rect.height();
 169   size_t bytes_limit = kMemoryMultiplier * kBytesPerPixel * width * height;
 170   // Round up to a multiple of kMemoryAllocationStep.
 171   bytes_limit =
 172       (bytes_limit / kMemoryAllocationStep + 1) * kMemoryAllocationStep;
 173   return bytes_limit;
 174 }
 175
 176 void BrowserViewRenderer::PrepareToDraw(const gfx::Vector2d& scroll,
 177                                         const gfx::Rect& global_visible_rect) {
 178   last_on_draw_scroll_offset_ = scroll;
 179   last_on_draw_global_visible_rect_ = global_visible_rect;
 180 }
 181
 182 bool BrowserViewRenderer::CanOnDraw() {
 183   if (!compositor_) {
 184     TRACE_EVENT_INSTANT0("android_webview", "EarlyOut_NoCompositor",
 185                          TRACE_EVENT_SCOPE_THREAD);
 186     return false;
 187   }
 188   if (clear_view_) {
 189     TRACE_EVENT_INSTANT0("android_webview", "EarlyOut_ClearView",
 190                          TRACE_EVENT_SCOPE_THREAD);
 191     return false;
 192   }
 193
 194   return true;
 195 }
 196
 197 bool BrowserViewRenderer::OnDrawHardware() {
 198   TRACE_EVENT0("android_webview", "BrowserViewRenderer::OnDrawHardware");
 199
 200   shared_renderer_state_.InitializeHardwareDrawIfNeededOnUI();
 201
 202   if (!CanOnDraw()) {
 203     return false;
 204   }
 205
 206   shared_renderer_state_.SetScrollOffsetOnUI(last_on_draw_scroll_offset_);
 207
 208   if (!hardware_enabled_) {
 209     TRACE_EVENT0("android_webview", "InitializeHwDraw");
 210     hardware_enabled_ = compositor_->InitializeHwDraw();
 211   }
 212   if (!hardware_enabled_) {
 213     TRACE_EVENT_INSTANT0("android_webview", "EarlyOut_HardwareNotEnabled",
 214                          TRACE_EVENT_SCOPE_THREAD);
 215     return false;
 216   }
 217
 218   return CompositeHw();
 219 }
 220
 221 bool BrowserViewRenderer::CompositeHw() {
 222   CancelFallbackTick();
 223
 224   ReturnResourceFromParent();
 225   compositor_->SetMemoryPolicy(CalculateDesiredMemoryPolicy());
 226
 227   ParentCompositorDrawConstraints parent_draw_constraints =
 228       shared_renderer_state_.GetParentDrawConstraintsOnUI();
 229   gfx::Size surface_size(size_);
 230   gfx::Rect viewport(surface_size);
 231   gfx::Rect clip = viewport;
 232   gfx::Transform transform_for_tile_priority =
 233       parent_draw_constraints.transform;
 234
 235   // If the WebView is on a layer, WebView does not know what transform is
 236   // applied onto the layer so global visible rect does not make sense here.
 237   // In this case, just use the surface rect for tiling.
 238   gfx::Rect viewport_rect_for_tile_priority;
 239
 240   // Leave viewport_rect_for_tile_priority empty if offscreen_pre_raster_ is on.
 241   if (!offscreen_pre_raster_) {
 242     if (parent_draw_constraints.is_layer) {
 243       viewport_rect_for_tile_priority = parent_draw_constraints.surface_rect;
 244     } else {
 245       viewport_rect_for_tile_priority = last_on_draw_global_visible_rect_;
 246     }
 247   }
 248
 249   scoped_ptr<cc::CompositorFrame> frame =
 250       compositor_->DemandDrawHw(surface_size,
 251                                 gfx::Transform(),
 252                                 viewport,
 253                                 clip,
 254                                 viewport_rect_for_tile_priority,
 255                                 transform_for_tile_priority);
 256   if (!frame.get()) {
 257     TRACE_EVENT_INSTANT0("android_webview", "NoNewFrame",
 258                          TRACE_EVENT_SCOPE_THREAD);
 259     return false;
 260   }
 261
 262   scoped_ptr<ChildFrame> child_frame = make_scoped_ptr(
 263       new ChildFrame(frame.Pass(), viewport_rect_for_tile_priority,
 264                      transform_for_tile_priority, offscreen_pre_raster_,
 265                      parent_draw_constraints.is_layer));
 266
 267   // Uncommitted frame can happen with consecutive fallback ticks.
 268   ReturnUnusedResource(shared_renderer_state_.PassUncommittedFrameOnUI());
 269   shared_renderer_state_.SetCompositorFrameOnUI(child_frame.Pass());
 270   return true;
 271 }
 272
 273 void BrowserViewRenderer::UpdateParentDrawConstraints() {
 274   PostInvalidateWithFallback();
 275   ParentCompositorDrawConstraints parent_draw_constraints =
 276       shared_renderer_state_.GetParentDrawConstraintsOnUI();
 277   client_->ParentDrawConstraintsUpdated(parent_draw_constraints);
 278 }
 279
 280 void BrowserViewRenderer::ReturnUnusedResource(
 281     scoped_ptr<ChildFrame> child_frame) {
 282   if (!child_frame.get() || !child_frame->frame.get())
 283     return;
 284
 285   cc::CompositorFrameAck frame_ack;
 286   cc::TransferableResource::ReturnResources(
 287       child_frame->frame->delegated_frame_data->resource_list,
 288       &frame_ack.resources);
 289   if (compositor_ && !frame_ack.resources.empty())
 290     compositor_->ReturnResources(frame_ack);
 291 }
 292
 293 void BrowserViewRenderer::ReturnResourceFromParent() {
 294   cc::CompositorFrameAck frame_ack;
 295   shared_renderer_state_.SwapReturnedResourcesOnUI(&frame_ack.resources);
 296   if (compositor_ && !frame_ack.resources.empty()) {
 297     compositor_->ReturnResources(frame_ack);
 298   }
 299 }
 300
 301 void BrowserViewRenderer::DetachFunctorFromView() {
 302   client_->DetachFunctorFromView();
 303 }
 304
 305 bool BrowserViewRenderer::OnDrawSoftware(SkCanvas* canvas) {
 306   return CanOnDraw() && CompositeSW(canvas);
 307 }
 308
 309 skia::RefPtr<SkPicture> BrowserViewRenderer::CapturePicture(int width,
 310                                                             int height) {
 311   TRACE_EVENT0("android_webview", "BrowserViewRenderer::CapturePicture");
 312
 313   // Return empty Picture objects for empty SkPictures.
 314   if (width <= 0 || height <= 0) {
 315     SkPictureRecorder emptyRecorder;
 316     emptyRecorder.beginRecording(0, 0);
 317     return skia::AdoptRef(emptyRecorder.endRecording());
 318   }
 319
 320   // Reset scroll back to the origin, will go back to the old
 321   // value when scroll_reset is out of scope.
 322   base::AutoReset<gfx::Vector2dF> scroll_reset(&scroll_offset_dip_,
 323                                                gfx::Vector2dF());
 324
 325   SkPictureRecorder recorder;
 326   SkCanvas* rec_canvas = recorder.beginRecording(width, height, NULL, 0);
 327   if (compositor_)
 328     CompositeSW(rec_canvas);
 329   return skia::AdoptRef(recorder.endRecording());
 330 }
 331
 332 void BrowserViewRenderer::EnableOnNewPicture(bool enabled) {
 333   on_new_picture_enable_ = enabled;
 334 }
 335
 336 void BrowserViewRenderer::ClearView() {
 337   TRACE_EVENT_INSTANT0("android_webview",
 338                        "BrowserViewRenderer::ClearView",
 339                        TRACE_EVENT_SCOPE_THREAD);
 340   if (clear_view_)
 341     return;
 342
 343   clear_view_ = true;
 344   // Always invalidate ignoring the compositor to actually clear the webview.
 345   PostInvalidateWithFallback();
 346 }
 347
 348 void BrowserViewRenderer::SetOffscreenPreRaster(bool enable) {
 349   // TODO(hush): anything to do when the setting is toggled?
 350   offscreen_pre_raster_ = enable;
 351 }
 352
 353 void BrowserViewRenderer::SetIsPaused(bool paused) {
 354   TRACE_EVENT_INSTANT1("android_webview",
 355                        "BrowserViewRenderer::SetIsPaused",
 356                        TRACE_EVENT_SCOPE_THREAD,
 357                        "paused",
 358                        paused);
 359   is_paused_ = paused;
 360   UpdateCompositorIsActive();
 361 }
 362
 363 void BrowserViewRenderer::SetViewVisibility(bool view_visible) {
 364   TRACE_EVENT_INSTANT1("android_webview",
 365                        "BrowserViewRenderer::SetViewVisibility",
 366                        TRACE_EVENT_SCOPE_THREAD,
 367                        "view_visible",
 368                        view_visible);
 369   view_visible_ = view_visible;
 370 }
 371
 372 void BrowserViewRenderer::SetWindowVisibility(bool window_visible) {
 373   TRACE_EVENT_INSTANT1("android_webview",
 374                        "BrowserViewRenderer::SetWindowVisibility",
 375                        TRACE_EVENT_SCOPE_THREAD,
 376                        "window_visible",
 377                        window_visible);
 378   window_visible_ = window_visible;
 379   UpdateCompositorIsActive();
 380 }
 381
 382 void BrowserViewRenderer::OnSizeChanged(int width, int height) {
 383   TRACE_EVENT_INSTANT2("android_webview",
 384                        "BrowserViewRenderer::OnSizeChanged",
 385                        TRACE_EVENT_SCOPE_THREAD,
 386                        "width",
 387                        width,
 388                        "height",
 389                        height);
 390   size_.SetSize(width, height);
 391 }
 392
 393 void BrowserViewRenderer::OnAttachedToWindow(int width, int height) {
 394   TRACE_EVENT2("android_webview",
 395                "BrowserViewRenderer::OnAttachedToWindow",
 396                "width",
 397                width,
 398                "height",
 399                height);
 400   attached_to_window_ = true;
 401   size_.SetSize(width, height);
 402   UpdateCompositorIsActive();
 403 }
 404
 405 void BrowserViewRenderer::OnDetachedFromWindow() {
 406   TRACE_EVENT0("android_webview", "BrowserViewRenderer::OnDetachedFromWindow");
 407   shared_renderer_state_.ReleaseHardwareDrawIfNeededOnUI();
 408   attached_to_window_ = false;
 409   DCHECK(!hardware_enabled_);
 410   UpdateCompositorIsActive();
 411 }
 412
 413 void BrowserViewRenderer::ReleaseHardware() {
 414   DCHECK(hardware_enabled_);
 415   ReturnUnusedResource(shared_renderer_state_.PassUncommittedFrameOnUI());
 416   ReturnResourceFromParent();
 417   DCHECK(shared_renderer_state_.ReturnedResourcesEmptyOnUI());
 418
 419   if (compositor_) {
 420     compositor_->ReleaseHwDraw();
 421   }
 422
 423   hardware_enabled_ = false;
 424 }
 425
 426 bool BrowserViewRenderer::IsVisible() const {
 427   // Ignore |window_visible_| if |attached_to_window_| is false.
 428   return view_visible_ && (!attached_to_window_ || window_visible_);
 429 }
 430
 431 gfx::Rect BrowserViewRenderer::GetScreenRect() const {
 432   return gfx::Rect(client_->GetLocationOnScreen(), size_);
 433 }
 434
 435 void BrowserViewRenderer::DidInitializeCompositor(
 436     content::SynchronousCompositor* compositor) {
 437   TRACE_EVENT0("android_webview",
 438                "BrowserViewRenderer::DidInitializeCompositor");
 439   DCHECK(compositor);
 440   DCHECK(!compositor_);
 441   compositor_ = compositor;
 442   UpdateCompositorIsActive();
 443 }
 444
 445 void BrowserViewRenderer::DidDestroyCompositor(
 446     content::SynchronousCompositor* compositor) {
 447   TRACE_EVENT0("android_webview", "BrowserViewRenderer::DidDestroyCompositor");
 448   DCHECK(compositor_);
 449   compositor_ = NULL;
 450 }
 451
 452 void BrowserViewRenderer::SetDipScale(float dip_scale) {
 453   dip_scale_ = dip_scale;
 454   CHECK_GT(dip_scale_, 0.f);
 455 }
 456
 457 gfx::Vector2d BrowserViewRenderer::max_scroll_offset() const {
 458   DCHECK_GT(dip_scale_, 0.f);
 459   return gfx::ToCeiledVector2d(gfx::ScaleVector2d(
 460       max_scroll_offset_dip_, dip_scale_ * page_scale_factor_));
 461 }
 462
 463 void BrowserViewRenderer::ScrollTo(gfx::Vector2d scroll_offset) {
 464   gfx::Vector2d max_offset = max_scroll_offset();
 465   gfx::Vector2dF scroll_offset_dip;
 466   // To preserve the invariant that scrolling to the maximum physical pixel
 467   // value also scrolls to the maximum dip pixel value we transform the physical
 468   // offset into the dip offset by using a proportion (instead of dividing by
 469   // dip_scale * page_scale_factor).
 470   if (max_offset.x()) {
 471     scroll_offset_dip.set_x((scroll_offset.x() * max_scroll_offset_dip_.x()) /
 472                             max_offset.x());
 473   }
 474   if (max_offset.y()) {
 475     scroll_offset_dip.set_y((scroll_offset.y() * max_scroll_offset_dip_.y()) /
 476                             max_offset.y());
 477   }
 478
 479   DCHECK_LE(0.f, scroll_offset_dip.x());
 480   DCHECK_LE(0.f, scroll_offset_dip.y());
 481   DCHECK(scroll_offset_dip.x() < max_scroll_offset_dip_.x() ||
 482          scroll_offset_dip.x() - max_scroll_offset_dip_.x() < kEpsilon)
 483       << scroll_offset_dip.x() << " " << max_scroll_offset_dip_.x();
 484   DCHECK(scroll_offset_dip.y() < max_scroll_offset_dip_.y() ||
 485          scroll_offset_dip.y() - max_scroll_offset_dip_.y() < kEpsilon)
 486       << scroll_offset_dip.y() << " " << max_scroll_offset_dip_.y();
 487
 488   if (scroll_offset_dip_ == scroll_offset_dip)
 489     return;
 490
 491   scroll_offset_dip_ = scroll_offset_dip;
 492
 493   TRACE_EVENT_INSTANT2("android_webview",
 494                "BrowserViewRenderer::ScrollTo",
 495                TRACE_EVENT_SCOPE_THREAD,
 496                "x",
 497                scroll_offset_dip.x(),
 498                "y",
 499                scroll_offset_dip.y());
 500
 501   if (compositor_)
 502     compositor_->DidChangeRootLayerScrollOffset();
 503 }
 504
 505 void BrowserViewRenderer::DidUpdateContent() {
 506   TRACE_EVENT_INSTANT0("android_webview",
 507                        "BrowserViewRenderer::DidUpdateContent",
 508                        TRACE_EVENT_SCOPE_THREAD);
 509   clear_view_ = false;
 510   if (on_new_picture_enable_)
 511     client_->OnNewPicture();
 512 }
 513
 514 void BrowserViewRenderer::SetTotalRootLayerScrollOffset(
 515     gfx::Vector2dF scroll_offset_dip) {
 516   // TOOD(mkosiba): Add a DCHECK to say that this does _not_ get called during
 517   // DrawGl when http://crbug.com/249972 is fixed.
 518   if (scroll_offset_dip_ == scroll_offset_dip)
 519     return;
 520
 521   scroll_offset_dip_ = scroll_offset_dip;
 522
 523   gfx::Vector2d max_offset = max_scroll_offset();
 524   gfx::Vector2d scroll_offset;
 525   // For an explanation as to why this is done this way see the comment in
 526   // BrowserViewRenderer::ScrollTo.
 527   if (max_scroll_offset_dip_.x()) {
 528     scroll_offset.set_x((scroll_offset_dip.x() * max_offset.x()) /
 529                         max_scroll_offset_dip_.x());
 530   }
 531
 532   if (max_scroll_offset_dip_.y()) {
 533     scroll_offset.set_y((scroll_offset_dip.y() * max_offset.y()) /
 534                         max_scroll_offset_dip_.y());
 535   }
 536
 537   DCHECK_LE(0, scroll_offset.x());
 538   DCHECK_LE(0, scroll_offset.y());
 539   DCHECK_LE(scroll_offset.x(), max_offset.x());
 540   DCHECK_LE(scroll_offset.y(), max_offset.y());
 541
 542   client_->ScrollContainerViewTo(scroll_offset);
 543 }
 544
 545 gfx::Vector2dF BrowserViewRenderer::GetTotalRootLayerScrollOffset() {
 546   return scroll_offset_dip_;
 547 }
 548
 549 bool BrowserViewRenderer::IsExternalFlingActive() const {
 550   return client_->IsFlingActive();
 551 }
 552
 553 void BrowserViewRenderer::UpdateRootLayerState(
 554     const gfx::Vector2dF& total_scroll_offset_dip,
 555     const gfx::Vector2dF& max_scroll_offset_dip,
 556     const gfx::SizeF& scrollable_size_dip,
 557     float page_scale_factor,
 558     float min_page_scale_factor,
 559     float max_page_scale_factor) {
 560   TRACE_EVENT_INSTANT1(
 561       "android_webview",
 562       "BrowserViewRenderer::UpdateRootLayerState",
 563       TRACE_EVENT_SCOPE_THREAD,
 564       "state",
 565       RootLayerStateAsValue(total_scroll_offset_dip, scrollable_size_dip));
 566
 567   DCHECK_GT(dip_scale_, 0.f);
 568
 569   max_scroll_offset_dip_ = max_scroll_offset_dip;
 570   DCHECK_LE(0.f, max_scroll_offset_dip_.x());
 571   DCHECK_LE(0.f, max_scroll_offset_dip_.y());
 572
 573   page_scale_factor_ = page_scale_factor;
 574   DCHECK_GT(page_scale_factor_, 0.f);
 575
 576   client_->UpdateScrollState(max_scroll_offset(),
 577                              scrollable_size_dip,
 578                              page_scale_factor,
 579                              min_page_scale_factor,
 580                              max_page_scale_factor);
 581   SetTotalRootLayerScrollOffset(total_scroll_offset_dip);
 582 }
 583
 584 scoped_refptr<base::trace_event::ConvertableToTraceFormat>
 585 BrowserViewRenderer::RootLayerStateAsValue(
 586     const gfx::Vector2dF& total_scroll_offset_dip,
 587     const gfx::SizeF& scrollable_size_dip) {
 588   scoped_refptr<base::trace_event::TracedValue> state =
 589       new base::trace_event::TracedValue();
 590
 591   state->SetDouble("total_scroll_offset_dip.x", total_scroll_offset_dip.x());
 592   state->SetDouble("total_scroll_offset_dip.y", total_scroll_offset_dip.y());
 593
 594   state->SetDouble("max_scroll_offset_dip.x", max_scroll_offset_dip_.x());
 595   state->SetDouble("max_scroll_offset_dip.y", max_scroll_offset_dip_.y());
 596
 597   state->SetDouble("scrollable_size_dip.width", scrollable_size_dip.width());
 598   state->SetDouble("scrollable_size_dip.height", scrollable_size_dip.height());
 599
 600   state->SetDouble("page_scale_factor", page_scale_factor_);
 601   return state;
 602 }
 603
 604 void BrowserViewRenderer::DidOverscroll(gfx::Vector2dF accumulated_overscroll,
 605                                         gfx::Vector2dF latest_overscroll_delta,
 606                                         gfx::Vector2dF current_fling_velocity) {
 607   const float physical_pixel_scale = dip_scale_ * page_scale_factor_;
 608   if (accumulated_overscroll == latest_overscroll_delta)
 609     overscroll_rounding_error_ = gfx::Vector2dF();
 610   gfx::Vector2dF scaled_overscroll_delta =
 611       gfx::ScaleVector2d(latest_overscroll_delta, physical_pixel_scale);
 612   gfx::Vector2d rounded_overscroll_delta = gfx::ToRoundedVector2d(
 613       scaled_overscroll_delta + overscroll_rounding_error_);
 614   overscroll_rounding_error_ =
 615       scaled_overscroll_delta - rounded_overscroll_delta;
 616   client_->DidOverscroll(rounded_overscroll_delta);
 617 }
 618
 619 void BrowserViewRenderer::PostInvalidate() {
 620   TRACE_EVENT_INSTANT0("android_webview", "BrowserViewRenderer::PostInvalidate",
 621                        TRACE_EVENT_SCOPE_THREAD);
 622   PostInvalidateWithFallback();
 623 }
 624
 625 void BrowserViewRenderer::PostInvalidateWithFallback() {
 626   // Always call view invalidate. We rely the Android framework to ignore the
 627   // invalidate when it's not needed such as when view is not visible.
 628   client_->PostInvalidate();
 629
 630   // Stop fallback ticks when one of these is true.
 631   // 1) Webview is paused. Also need to check we are not in clear view since
 632   // paused, offscreen still expect clear view to recover.
 633   // 2) If we are attached to window and the window is not visible (eg when
 634   // app is in the background). We are sure in this case the webview is used
 635   // "on-screen" but that updates are not needed when in the background.
 636   bool throttle_fallback_tick =
 637       (is_paused_ && !clear_view_) || (attached_to_window_ && !window_visible_);
 638
 639   if (throttle_fallback_tick || fallback_tick_pending_)
 640     return;
 641
 642   DCHECK(post_fallback_tick_.IsCancelled());
 643   DCHECK(fallback_tick_fired_.IsCancelled());
 644
 645   post_fallback_tick_.Reset(base::Bind(&BrowserViewRenderer::PostFallbackTick,
 646                                        base::Unretained(this)));
 647   ui_task_runner_->PostTask(FROM_HERE, post_fallback_tick_.callback());
 648   fallback_tick_pending_ = true;
 649 }
 650
 651 void BrowserViewRenderer::CancelFallbackTick() {
 652   post_fallback_tick_.Cancel();
 653   fallback_tick_fired_.Cancel();
 654   fallback_tick_pending_ = false;
 655 }
 656
 657 void BrowserViewRenderer::PostFallbackTick() {
 658   DCHECK(fallback_tick_fired_.IsCancelled());
 659   TRACE_EVENT0("android_webview", "BrowserViewRenderer::PostFallbackTick");
 660   post_fallback_tick_.Cancel();
 661   fallback_tick_fired_.Reset(base::Bind(&BrowserViewRenderer::FallbackTickFired,
 662                                         base::Unretained(this)));
 663   ui_task_runner_->PostDelayedTask(
 664       FROM_HERE, fallback_tick_fired_.callback(),
 665       base::TimeDelta::FromMilliseconds(kFallbackTickTimeoutInMilliseconds));
 666 }
 667
 668 void BrowserViewRenderer::FallbackTickFired() {
 669   TRACE_EVENT0("android_webview", "BrowserViewRenderer::FallbackTickFired");
 670   // This should only be called if OnDraw or DrawGL did not come in time, which
 671   // means fallback_tick_pending_ must still be true.
 672   DCHECK(fallback_tick_pending_);
 673   fallback_tick_fired_.Cancel();
 674   fallback_tick_pending_ = false;
 675   if (compositor_) {
 676     if (hardware_enabled_) {
 677       CompositeHw();
 678     } else {
 679       ForceFakeCompositeSW();
 680     }
 681   }
 682 }
 683
 684 void BrowserViewRenderer::ForceFakeCompositeSW() {
 685   DCHECK(compositor_);
 686   SkBitmap bitmap;
 687   bitmap.allocN32Pixels(1, 1);
 688   bitmap.eraseColor(0);
 689   SkCanvas canvas(bitmap);
 690   CompositeSW(&canvas);
 691 }
 692
 693 bool BrowserViewRenderer::CompositeSW(SkCanvas* canvas) {
 694   DCHECK(compositor_);
 695   CancelFallbackTick();
 696   ReturnResourceFromParent();
 697   return compositor_->DemandDrawSw(canvas);
 698 }
 699
 700 void BrowserViewRenderer::UpdateCompositorIsActive() {
 701   if (compositor_)
 702     compositor_->SetIsActive(!is_paused_ &&
 703                              (!attached_to_window_ || window_visible_));
 704 }
 705
 706 std::string BrowserViewRenderer::ToString() const {
 707   std::string str;
 708   base::StringAppendF(&str, "is_paused: %d ", is_paused_);
 709   base::StringAppendF(&str, "view_visible: %d ", view_visible_);
 710   base::StringAppendF(&str, "window_visible: %d ", window_visible_);
 711   base::StringAppendF(&str, "dip_scale: %f ", dip_scale_);
 712   base::StringAppendF(&str, "page_scale_factor: %f ", page_scale_factor_);
 713   base::StringAppendF(&str, "fallback_tick_pending: %d ",
 714                       fallback_tick_pending_);
 715   base::StringAppendF(&str, "view size: %s ", size_.ToString().c_str());
 716   base::StringAppendF(&str, "attached_to_window: %d ", attached_to_window_);
 717   base::StringAppendF(&str,
 718                       "global visible rect: %s ",
 719                       last_on_draw_global_visible_rect_.ToString().c_str());
 720   base::StringAppendF(
 721       &str, "scroll_offset_dip: %s ", scroll_offset_dip_.ToString().c_str());
 722   base::StringAppendF(&str,
 723                       "overscroll_rounding_error_: %s ",
 724                       overscroll_rounding_error_.ToString().c_str());
 725   base::StringAppendF(
 726       &str, "on_new_picture_enable: %d ", on_new_picture_enable_);
 727   base::StringAppendF(&str, "clear_view: %d ", clear_view_);
 728   return str;
 729 }
 730
 731 }  // namespace android_webview