[android_webview] Use a fraction to calculate scroll offset.

android_webview/ has to expose scroll offset operations in physical
pixels while cc/ stores scroll offsets in dip pixels.
Unfortunately the physical pixel values android_webview/ exposes are
rounded so there is no such combination of rounding operations that
allows for scrolls to 'bottom' in one corrdinate space to always be
'flush' against the bottom edge in the other. The most natural
solution is to convert the scroll offset to the fraction of the
scroll range.
By using the max_scroll_offset value obtained directly from the compositor
we're also removing the need to delay scrolls since the content size
is always as recent as the scroll offset update.

BUG=261239

Review URL: https://codereview.chromium.org/23533051

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@225348 0039d316-1c4b-4281-b951-d872f2087c98
Move constants from ExtensionService to extension_misc.

These constants don't need to be on ExtensionService and add to the
overwhelming nature of this module.

BUG=162530

Review URL: https://codereview.chromium.org/23905009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@225349 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 225349
Support GL_TEXTURE_EXTERNAL_OES targets through the compositor

Will be useful later for video compositing (i.e. hardware decoders that
produces raw YUV frames).

BUG=167417
TEST=local build, unittests, run on CrOS snow

Review URL: https://codereview.chromium.org/23950010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@225350 0039d316-1c4b-4281-b951-d872f2087c98
cryptohome: Introduce EmptyVoidDBusMethodCallback()

So that clients don't need to define their own DoNothing function.

BUG=298592
TEST=none
R=hashimoto@chromium.org

Review URL: https://codereview.chromium.org/24707003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@225351 0039d316-1c4b-4281-b951-d872f2087c98
Trigger overlay scrollbar animation when the pointer is nearby.

When the mouse cursor is near a scrollbar, trigger the scrollbar animation
so it's easier to find and grab the thinning scrollbars.

BUG=274010

Review URL: https://codereview.chromium.org/23983035

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@225352 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 225351
SVN changes up to revision 225352