gpu: Bind dummy GL API when no context is current

ui/gl/gl_gl_api_implementation.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/gl/gl_gl_api_implementation.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "base/command_line.h"
 #include "base/strings/string_util.h"
 #include "ui/gl/gl_context.h"
 #include "ui/gl/gl_implementation.h"
 #include "ui/gl/gl_state_restorer.h"
 #include "ui/gl/gl_surface.h"
 #include "ui/gl/gl_switches.h"
 #include "ui/gl/gl_version_info.h"
 
 namespace gfx {
 
 // The GL Api being used. This could be g_real_gl or gl_trace_gl
 static GLApi* g_gl;
 // A GL Api that calls directly into the driver.
 static RealGLApi* g_real_gl;
+// A GL Api that does nothing but warn about illegal GL calls without a context
+// current.
+static NoContextGLApi* g_no_context_gl;
 // A GL Api that calls TRACE and then calls another GL api.
 static TraceGLApi* g_trace_gl;
 // GL version used when initializing dynamic bindings.
 static GLVersionInfo* g_version_info = NULL;
 
 namespace {
 
 static inline GLenum GetInternalFormat(GLenum internal_format) {
   if (gfx::GetGLImplementation() != gfx::kGLImplementationEGLGLES2) {
     if (internal_format == GL_BGRA_EXT || internal_format == GL_BGRA8_EXT)
@@ skipping 216 matching lines @@
   null_draw_bindings_enabled = enabled;
   return before;
 }
 
 void InitializeStaticGLBindingsGL() {
   g_current_gl_context_tls = new base::ThreadLocalPointer<GLApi>;
   g_driver_gl.InitializeStaticBindings();
   if (!g_real_gl) {
     g_real_gl = new RealGLApi();
     g_trace_gl = new TraceGLApi(g_real_gl);
+    g_no_context_gl = new NoContextGLApi();
   }
   g_real_gl->Initialize(&g_driver_gl);
   g_gl = g_real_gl;
   if (CommandLine::ForCurrentProcess()->HasSwitch(
       switches::kEnableGPUServiceTracing)) {
     g_gl = g_trace_gl;
   }
   SetGLToRealGLApi();
 }
 
 GLApi* GetCurrentGLApi() {
   return g_current_gl_context_tls->Get();
 }
 
 void SetGLApi(GLApi* api) {
   g_current_gl_context_tls->Set(api);
 }
 
 void SetGLToRealGLApi() {
   SetGLApi(g_gl);
 }
 
+void SetGLApiToNoContext() {
+  SetGLApi(g_no_context_gl);
+}
+
 void InitializeDynamicGLBindingsGL(GLContext* context) {
   g_driver_gl.InitializeCustomDynamicBindings(context);
   DCHECK(context && context->IsCurrent(NULL) && !g_version_info);
   g_version_info = new GLVersionInfo(context->GetGLVersion().c_str(),
       context->GetGLRenderer().c_str());
 }
 
 void InitializeDebugGLBindingsGL() {
   g_driver_gl.InitializeDebugBindings();
 }
@@ skipping 56 matching lines @@
 RealGLApi::~RealGLApi() {
 }
 
 void RealGLApi::Initialize(DriverGL* driver) {
   InitializeBase(driver);
 }
 
 TraceGLApi::~TraceGLApi() {
 }
 
+NoContextGLApi::NoContextGLApi() {
+}
+
+NoContextGLApi::~NoContextGLApi() {
+}
+
 VirtualGLApi::VirtualGLApi()
     : real_context_(NULL),
       current_context_(NULL) {
 }
 
 VirtualGLApi::~VirtualGLApi() {
 }
 
 void VirtualGLApi::Initialize(DriverGL* driver, GLContext* real_context) {
   InitializeBase(driver);
@@ skipping 70 matching lines @@
 const GLubyte* VirtualGLApi::glGetStringFn(GLenum name) {
   switch (name) {
     case GL_EXTENSIONS:
       return reinterpret_cast<const GLubyte*>(extensions_.c_str());
     default:
       return driver_->fn.glGetStringFn(name);
   }
 }
 
 }  // namespace gfx