Enable accelerated WebKit compositor for Aura.

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index 435f7e16a71271a0135cb9922bcc1696be66877c..e5685455129bd5929168b10679b65f1a275af0ce 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -327,6 +327,14 @@
           'proprietary_codecs%': 1,
           'enable_webrtc%': 0,
         }],
+
+        # Use GPU accelerated cross process image transport by default
+        # on TOUCH_UI and linux builds with the Aura window manager
+        ['views_compositor==1 and OS=="linux"', {
+          'views_gpu_image_transport%': 1,
+        }, {
+          'views_gpu_image_transport%': 0,
+        }],
       ],
     },
 
@@ -339,6 +347,7 @@
     'toolkit_views%': '<(toolkit_views)',
     'use_only_pure_views%': '<(use_only_pure_views)',
     'views_compositor%': '<(views_compositor)',
+    'views_gpu_image_transport%': '<(views_gpu_image_transport)',
     'use_aura%': '<(use_aura)',
     'use_openssl%': '<(use_openssl)',
     'use_nss%': '<(use_nss)',
@@ -380,6 +389,7 @@
     'asan%': '<(asan)',
     'enable_register_protocol_handler%': '<(enable_register_protocol_handler)',
     'enable_web_intents%': '<(enable_web_intents)',
+
     # Whether to build for Wayland display server
     'use_wayland%': 0,
 
@@ -931,6 +941,9 @@
       ['views_compositor==1', {
         'defines': ['VIEWS_COMPOSITOR=1'],
       }],
+      ['views_gpu_image_transport==1', {
+        'defines': ['VIEWS_GPU_IMAGE_TRANSPORT'],

[Ben Goodger (Google), 2011/10/12 18:22:58]

The only suggestion i'd have is not to tie the terminology of the #define to
views... 

GPU_IMAGE_TRANSPORT

RENDERER_GPU_IMAGE_TRANSPORT

.. etc since we will be using wiring the external texture directly to the
compositor layer in RWHVA (i.e. Views won't even be consulted). 

+      }],
       ['use_aura==1', {
         'defines': ['USE_AURA=1'],
       }],