cc: Remove DCHECK for invalid image

cc/resources/resource_provider.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 "cc/resources/resource_provider.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 1166 matching lines @@
     desc.fOrigin = kTopLeft_GrSurfaceOrigin;
     desc.fTextureHandle = skia::GrGLTextureInfoToGrBackendObject(texture_info);
     sk_image_ = SkImage::MakeFromTexture(
         resource_provider->compositor_context_provider_->GrContext(), desc);
   } else if (resource->pixels) {
     SkBitmap sk_bitmap;
     ResourceProvider::PopulateSkBitmapWithResource(&sk_bitmap, resource);
     sk_bitmap.setImmutable();
     sk_image_ = SkImage::MakeFromBitmap(sk_bitmap);
   } else {
-    NOTREACHED() << "Image not valid";
+    // TODO(enne): fix race condition of shared bitmap manager going away
+    // that can cause this to happen.  This will cause the read lock
+    // to not be valid.
   }
 }
 
 ResourceProvider::ScopedReadLockSkImage::~ScopedReadLockSkImage() {
   resource_provider_->UnlockForRead(resource_id_);
 }
 
 ResourceProvider::ScopedWriteLockSoftware::ScopedWriteLockSoftware(
     ResourceProvider* resource_provider,
     ResourceId resource_id)
@@ skipping 785 matching lines @@
 
     const int kImportance = 2;
     pmd->CreateSharedGlobalAllocatorDump(guid);
     pmd->AddOwnershipEdge(dump->guid(), guid, kImportance);
   }
 
   return true;
 }
 
 }  // namespace cc