Make it possible to use OSMesa on Android

ui/gl/gl_context_android.cc

Index: ui/gl/gl_context_android.cc
diff --git a/ui/gl/gl_context_android.cc b/ui/gl/gl_context_android.cc
index 9b266950a9aa6c169e6a42a9f64eb735b983ed4a..d9f5315624d9a9da11183a8b82b789b28cbccd83 100644
--- a/ui/gl/gl_context_android.cc
+++ b/ui/gl/gl_context_android.cc
@@ -10,6 +10,7 @@
 #include "base/sys_info.h"
 #include "ui/gl/gl_bindings.h"
 #include "ui/gl/gl_context_egl.h"
+#include "ui/gl/gl_context_osmesa.h"
 #include "ui/gl/gl_context_stub.h"
 #include "ui/gl/gl_implementation.h"
 #include "ui/gl/gl_surface.h"
@@ -75,16 +76,24 @@ scoped_refptr<GLContext> GLContext::CreateGLContext(
     GLShareGroup* share_group,
     GLSurface* compatible_surface,
     GpuPreference gpu_preference) {
-  if (GetGLImplementation() == kGLImplementationMockGL)
-    return scoped_refptr<GLContext>(new GLContextStub());
-
   scoped_refptr<GLContext> context;
-  if (compatible_surface->GetHandle())
-    context = new GLContextEGL(share_group);
-  else
-    context = new GLNonOwnedContext(share_group);
+  switch(GetGLImplementation()) {

[Sami, 2013/09/19 16:37:46]

Since you're here :) Could you change this to be a little more explicit about
what we support:

    switch(GetGLImplementation()) {
      case kGLImplementationMockGL:
        return scoped_refptr<GLContext>(new GLContextStub());
      case kGLImplementationOSMesaGL:
        context = new GLContextOSMesa(share_group);
        break;
      case kGLImplementationEGLGLES2:
        if (compatible_surface->GetHandle())
          context = new GLContextEGL(share_group);
        else
          context = new GLNonOwnedContext(share_group);
        break;
      default:
        NOTREACHED();
        return NULL;
    }

[Peter Beverloo, 2013/09/19 16:48:44]

Done.

+    case kGLImplementationMockGL:
+      return scoped_refptr<GLContext>(new GLContextStub());
+    case kGLImplementationOSMesaGL:
+      context = new GLContextOSMesa(share_group);
+      break;
+    default:
+      if (compatible_surface->GetHandle())
+        context = new GLContextEGL(share_group);
+      else
+        context = new GLNonOwnedContext(share_group);
+      break;
+  }
+
   if (!context->Initialize(compatible_surface, gpu_preference))
     return NULL;
+
   return context;
 }