Ensure GL initialization only happens once, and provide common init path

content/gpu/gpu_main.cc

Index: content/gpu/gpu_main.cc
diff --git a/content/gpu/gpu_main.cc b/content/gpu/gpu_main.cc
index f7650e7bd31410c0f700a0a2703e5e44d660e3bb..9e6160df18233afb38486087db7ffa7a60e1092e 100644
--- a/content/gpu/gpu_main.cc
+++ b/content/gpu/gpu_main.cc
@@ -219,8 +219,25 @@ int GpuMain(const MainFunctionParams& parameters) {
 
     base::TimeTicks before_initialize_one_off = base::TimeTicks::Now();
 
+    // Determine if we need to initialize GL here or it has already been done.
+    bool gl_already_initialized = false;
+#if defined(OS_MACOSX)
+    // On Mac, GLSurface::InitializeOneOff() is called from the sandbox warmup
+    // code before getting here.
+    gl_already_initialized = true;
+#endif
+    if (command_line.HasSwitch(switches::kInProcessGPU)) {
+      // With in-process GPU, GLSurface::InitializeOneOff() is called from
+      // GpuChildThread before getting here.
+      gl_already_initialized = true;
+    }
+
     // Load and initialize the GL implementation and locate the GL entry points.
-    if (gfx::GLSurface::InitializeOneOff()) {
+    bool gl_initialized =
+        gl_already_initialized
+            ? gfx::GetGLImplementation() != gfx::kGLImplementationNone
+            : gfx::GLSurface::InitializeOneOff();
+    if (gl_initialized) {
       // We need to collect GL strings (VENDOR, RENDERER) for blacklisting
       // purposes. However, on Mac we don't actually use them. As documented in
       // crbug.com/222934, due to some driver issues, glGetString could take