Move webkit/gpu into webkit/common/gpu

Move webkit/gpu into webkit/common/gpu

The code in webkit/gpu is needed everywhere the compositor is used, which means
both renderer and browser processes. This is a bit of a bummer but hard to fix
immediately since the compositor uses WebKit::WebGraphicsContext3D. webkit/gpu
itself only depends on the context type (which is just a vtable) and a couple
exported functions from WebString, so it's not the end of the world to have it
linked into every process. This moves the code into webkit/common/ to make this
clearer.

R=piman, joth
BUG=237267
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=202341

[piman, 2013-05-24 23:55:36]

lgtm

[jamesr, 2013-05-24 23:56:44]

Thanks! TBRing joth@ for the mechanical android_webview changes

[commit-bot: I haz the power, 2013-05-24 23:57:03]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/jamesr@chromium.org/16046003/1

[joth, 2013-05-24 23:57:36]

lgtm

[commit-bot: I haz the power, 2013-05-25 00:18:46]

Sorry for I got bad news for ya.
Compile failed with a clobber build on linux_chromeos_clang.
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=linux_chro...
Your code is likely broken or HEAD is junk. Please ensure your
code is not broken then alert the build sheriffs.
Look at the try server FAQ for more details.

[commit-bot: I haz the power, 2013-05-25 00:51:14]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/jamesr@chromium.org/16046003/13001

[commit-bot: I haz the power, 2013-05-26 02:44:20]

Commit queue rejected this change because the description was changed
between the time the change entered the commit queue and the time it
was ready to commit. You can safely check the commit box again.

[commit-bot: I haz the power, 2013-05-26 03:22:53]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/jamesr@chromium.org/16046003/13001

[commit-bot: I haz the power, 2013-05-26 03:23:49]

Change committed as 202341