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

git-svn-id: http://src.chromium.org/svn/trunk/src/base@289642 4ff67af0-8c30-449e-8e8b-ad334ec8d88c
gn win: re-add event_recorder_stubs.cc, mistakenly removed before

(This matches the gyp build)

R=brettw@chromium.org
TBR=brettw@chromium.org
BUG=354261

Review URL: https://codereview.chromium.org/467413002

git-svn-id: http://src.chromium.org/svn/trunk/src/base@289657 4ff67af0-8c30-449e-8e8b-ad334ec8d88c
Remove restriction on x64 chromium linker builds.

As of r287591 the android chromium linker supports EM_X86_64 and x86_64
relocations.  Remove the restriction preventing libchromium_android_linker.so
building when arch=x64.

BUG=369133

Review URL: https://codereview.chromium.org/470133003

git-svn-id: http://src.chromium.org/svn/trunk/src/base@289683 4ff67af0-8c30-449e-8e8b-ad334ec8d88c