Fix cpplint warnings.
Fixes:
base/android/linker/linker_jni.cc:300: Single-parameter constructors should be marked explicit. [runtime/explicit] [5]
base/android/linker/linker_jni.cc:313: Weird number of spaces at line-start. Are you using a 2-space indent? [whitespace/indent] [3]
base/android/linker/linker_jni.cc:319: Weird number of spaces at line-start. Are you using a 2-space indent? [whitespace/indent] [3]
base/android/linker/linker_jni.cc:320: Weird number of spaces at line-start. Are you using a 2-space indent? [whitespace/indent] [3]
BUG=
Review URL: https://codereview.chromium.org/
470943002
Cr-Commit-Position: refs/heads/master@{#289642}
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@289642 0039d316-1c4b-4281-b951-d872f2087c98