Fix crashers and issues when rendering blimp in tabs

chrome/browser/android/tab_android.cc

 // Copyright 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 "chrome/browser/android/tab_android.h"
 
 #include <stddef.h>
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_string.h"
@@ skipping 416 matching lines @@
     const JavaParamRef<jobject>& j_profile,
     jlong window_android_ptr) {
   Profile* profile = ProfileAndroid::FromProfileAndroid(j_profile.obj());
   DCHECK(!profile->IsOffTheRecord());
   blimp::client::BlimpClientContext* context =
       BlimpClientContextFactory::GetForBrowserContext(profile);
   DCHECK(context);
   ui::WindowAndroid* window =
       reinterpret_cast<ui::WindowAndroid*>(window_android_ptr);
   blimp_contents_ = context->CreateBlimpContents(window);
-  DCHECK(blimp_contents_);
+  // If creating a BlimpContents failed, fall back to WebContents-based by
+  // doing an early out here.
+  if (!blimp_contents_)
+    return nullptr;
 
   // Let's detach the layer from WebContents first, just to be sure.
   if (web_contents_ && web_contents_->GetNativeView() &&
       web_contents_->GetNativeView()->GetLayer()) {
     cc::Layer* web_contents_layer = web_contents_->GetNativeView()->GetLayer();
     if (web_contents_layer->parent() == content_layer_.get())
       web_contents_layer->RemoveFromParent();
   }
 
   // Attach the layer holding the tab contents to the |content_layer_|.
@@ skipping 467 matching lines @@
 static void Init(JNIEnv* env, const JavaParamRef<jobject>& obj) {
   TRACE_EVENT0("native", "TabAndroid::Init");
   // This will automatically bind to the Java object and pass ownership there.
   new TabAndroid(env, obj);
 }
 
 // static
 bool TabAndroid::RegisterTabAndroid(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }