Make it possible to use OSMesa on Android

ui/gl/gl_implementation_android.cc

Index: ui/gl/gl_implementation_android.cc
diff --git a/ui/gl/gl_implementation_android.cc b/ui/gl/gl_implementation_android.cc
index f644866b3d8e0aa257619b837ba50f77077913d2..20c7f23eb0ef39ca1a2547cd9a27a75444dc9e95 100644
--- a/ui/gl/gl_implementation_android.cc
+++ b/ui/gl/gl_implementation_android.cc
@@ -45,6 +45,37 @@ base::NativeLibrary LoadLibrary(const char* filename) {
 
 void GetAllowedGLImplementations(std::vector<GLImplementation>* impls) {
   impls->push_back(kGLImplementationEGLGLES2);
+  impls->push_back(kGLImplementationOSMesaGL);
+}
+
+bool InitializeGLBindingsOSMesaGL() {
+  base::FilePath module_path;
+  if (!PathService::Get(base::DIR_MODULE, &module_path)) {
+    LOG(ERROR) << "PathService::Get failed.";
+    return false;
+  }
+
+  base::NativeLibrary library = LoadLibrary(module_path.Append("libosmesa.so"));
+  if (!library)
+    return false;
+
+  GLGetProcAddressProc get_proc_address =
+      reinterpret_cast<GLGetProcAddressProc>(
+          base::GetFunctionPointerFromNativeLibrary(library,
+                                                    "OSMesaGetProcAddress"));
+  if (!get_proc_address) {
+    LOG(ERROR) << "OSMesaGetProcAddress not found.";
+    base::UnloadNativeLibrary(library);
+    return false;
+  }
+
+  SetGLGetProcAddressProc(get_proc_address);
+  AddGLNativeLibrary(library);
+  SetGLImplementation(kGLImplementationOSMesaGL);
+
+  InitializeGLBindingsGL();
+  InitializeGLBindingsOSMESA();
+  return true;
 }
 
 bool InitializeGLBindings(GLImplementation implementation) {
@@ -90,6 +121,8 @@ bool InitializeGLBindings(GLImplementation implementation) {
       ::gfx::g_driver_gl.fn.glDepthRangeFn = MarshalDepthRangeToDepthRangef;
       break;
     }
+    case kGLImplementationOSMesaGL:
+      return InitializeGLBindingsOSMesaGL();
     case kGLImplementationMockGL: {
       SetGLGetProcAddressProc(GetMockGLProcAddress);
       SetGLImplementation(kGLImplementationMockGL);
@@ -111,6 +144,10 @@ bool InitializeGLExtensionBindings(GLImplementation implementation,
       InitializeGLExtensionBindingsGL(context);
       InitializeGLExtensionBindingsEGL(context);
       break;
+    case kGLImplementationOSMesaGL:
+      InitializeGLExtensionBindingsGL(context);
+      InitializeGLExtensionBindingsOSMESA(context);
+      break;
     case kGLImplementationMockGL:
       InitializeGLExtensionBindingsGL(context);
       break;