Added about:flags entries for --enable-accelerated-drawing flag.

chrome/app/generated_resources.grd

Index: chrome/app/generated_resources.grd
===================================================================
--- chrome/app/generated_resources.grd	(revision 89675)
+++ chrome/app/generated_resources.grd	(working copy)
@@ -4157,6 +4157,12 @@
       <message name="IDS_FLAGS_COMPOSITED_LAYER_BORDERS_DESCRIPTION" desc="Description of the 'Composited layer borders' lab.">
         Renders a border around composited Render Layers to help debug and study layer compositing.
       </message>
+      <message name="IDS_FLAGS_ACCELERATED_DRAWING_NAME" desc="Title for the flag to enable accelerated drawing">
+        GPU Accelerated Drawing
+      </message>
+      <message name="IDS_FLAGS_ACCELERATED_DRAWING_DESCRIPTION" desc="Description for the flag to enable accelerated drawing">
+        Enable GPU accelerated drawing of composited render layers.

[vangelis, 2011/06/20 18:06:51]

Since essentially all rendering in the page (including the root layer) will be
going through the GPU should the be phrased as:

"Enable GPU accelerated drawing of page contents"

or something like that?  Also, what happens if accelerated drawing is enabled
without force compositing mode?  Should one trigger the other? If not, we should
probably put a brief blurb here that it also requires the force compositing flag
to be enabled.

[alokp, 2011/06/20 19:01:18]

Isn't root layer a composited render layer? I think "composited render layers"
is more appropriate than "page contents" because it only comes into effect when
compositing is active.
DONE.

[vangelis, 2011/06/20 19:27:47]

The root is currently a special case and not treated like the rest of the
content layers.  In any case though, since this is a user facing message that
distinction would be lost.

You are right that we need to somehow indicate that this only affects pages that
go through the compositor. I think it could be clearer if we say that this does
accelerated drawing for the contents of the layer (as opposed to an accelerated
compositing operation).

"Enable GPU accelerated drawing of page contents when compositing is enabled."

?

[alokp, 2011/06/20 19:33:38]

perfect! DONE.

+      </message>
       <message name="IDS_FLAGS_SHOW_FPS_COUNTER" desc="Name of the 'Show FPS counter' lab.">
         FPS counter
       </message>