Exposed support for dynamically enabling extensions in command buffer

implementation via new glGetRequestableExtensionsCHROMIUM and
glRequestExtensionCHROMIUM entry points. These entry points are needed in
order to allow WebGL to both query the available extensions and enable them
individually.

Added these entry points to WebGraphicsContext3DCommandBufferImpl. A
subsequent WebKit checkin under https://bugs.webkit.org/show_bug.cgi?id=40316
will utilize them and implement the OES_texture_float extension for WebGL.

BUG=none
TEST=none (ran with new oes-texture-float.html WebGL conformance test)

Review URL: http://codereview.chromium.org/5626008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@68352 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 16 insertions, 5 deletions

diff --git a/gpu/command_buffer/service/feature_info.cc b/gpu/command_buffer/service/feature_info.cc
index cf755d8..5d9403e 100644
--- a/gpu/command_buffer/service/feature_info.cc
+++ b/gpu/command_buffer/service/feature_info.cc
@@ -215,21 +215,32 @@ void FeatureInfo::AddFeatures(const char* desired_features) {
   bool enable_texture_float_linear = false;
   bool enable_texture_half_float = false;
   bool enable_texture_half_float_linear = false;
-  if (ext.HaveAndDesire("GL_ARB_texture_float")) {
+
+  bool have_arb_texture_float = ext.Have("GL_ARB_texture_float");
+
+  if (have_arb_texture_float && ext.Desire("GL_ARB_texture_float")) {
     enable_texture_float = true;
     enable_texture_float_linear = true;
     enable_texture_half_float = true;
     enable_texture_half_float_linear = true;
   } else {
-    if (ext.HaveAndDesire("GL_OES_texture_float")) {
+    if (ext.HaveAndDesire("GL_OES_texture_float") ||
+        (have_arb_texture_float &&
+         ext.Desire("GL_OES_texture_float"))) {
       enable_texture_float = true;
-      if (ext.HaveAndDesire("GL_OES_texture_float_linear")) {
+      if (ext.HaveAndDesire("GL_OES_texture_float_linear") ||
+          (have_arb_texture_float &&
+           ext.Desire("GL_OES_texture_float_linear"))) {
         enable_texture_float_linear = true;
       }
     }
-    if (ext.HaveAndDesire("GL_OES_texture_half_float")) {
+    if (ext.HaveAndDesire("GL_OES_texture_half_float") ||
+        (have_arb_texture_float &&
+         ext.Desire("GL_OES_texture_half_float"))) {
       enable_texture_half_float = true;
-      if (ext.HaveAndDesire("GL_OES_texture_half_float_linear")) {
+      if (ext.HaveAndDesire("GL_OES_texture_half_float_linear") ||
+          (have_arb_texture_float &&
+           ext.Desire("GL_OES_texture_half_float_linear"))) {
         enable_texture_half_float_linear = true;
       }
     }