Bug 994024 - Discard TextureClients that we failed to allocate or lock. r=bjacob

gfx/layers/client/CanvasClient.cpp

@@ -81,6 +81,7 @@ CanvasClient2D::Update(gfx::IntSize aSize, ClientCanvasLayer* aLayer)
   }
 
   if (!mBuffer->Lock(OPEN_WRITE_ONLY)) {
+    mBuffer = nullptr;
     return;
   }
 

gfx/layers/client/ImageClient.cpp

@@ -176,6 +176,7 @@ ImageClientSingle::UpdateImageInternal(ImageContainer* aContainer,
     }
 
     if (!mFrontBuffer->Lock(OPEN_WRITE_ONLY)) {
+      mFrontBuffer = nullptr;
       return false;
     }
     bool status = mFrontBuffer->AsTextureClientYCbCr()->UpdateYCbCr(*data);
@@ -243,6 +244,7 @@ ImageClientSingle::UpdateImageInternal(ImageContainer* aContainer,
     }
 
     if (!mFrontBuffer->Lock(OPEN_WRITE_ONLY)) {
+      mFrontBuffer = nullptr;
       return false;
     }