Implement stream based cross file system copy.

This CL implements the FileStreamReader/Writer based cross file system copy
operation.

BUG=279278
TEST=Ran content_unittests and unit_tests

Review URL: https://codereview.chromium.org/23463048

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@225378 0039d316-1c4b-4281-b951-d872f2087c98
Use GL_TEXTURE_2D for pixel readback path in GpuVideoAcceleratorFactories

Using the destination texture target in
GpuVideoAcceleratorFactores::ReadPixels is incorrect, as the temporary texture
should always be GL_TEXTURE_2D.

BUG=None
TEST=local build, run on CrOS snow, unittests on desktop Linux

Review URL: https://codereview.chromium.org/23542060

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@225379 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 225378
[PPAPI] ResourceVar now holds a pending renderer and browser host ID.

It is likely that resources will be backed by a host in the renderer or
browser, or both. Therefore, HostResourceVar should provide a consistent
way to tell the plugin the pending host IDs.

BUG=177017

Review URL: https://codereview.chromium.org/24196005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@225380 0039d316-1c4b-4281-b951-d872f2087c98
Rename class Cpu to CpuMetric, for consistency with other Metric classes

BUG=

Review URL: https://codereview.chromium.org/24278010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@225381 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 225381