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 f4555a2c28f93fba09d8e5f8c10afff3cd992a2d..2b918929ddd0f2bf87ca0428f1ab1650adc6e6a5 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()) {
+    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;
 }