Check If ImageBuffer is allocated before proceeding.

This patch takes care of the left out places where 
newly created ImageBuffer is not validated.

BUG= 248420

Review URL: https://codereview.chromium.org/562543004

git-svn-id: svn://svn.chromium.org/blink/trunk@181936 bbb929c8-8fbe-4397-9dbb-9b2b20218538

Source/core/rendering/svg/RenderSVGResourceFilter.cpp

@@ -131,6 +131,8 @@ static bool createImageBuffer(const Filter* filter, OwnPtr<ImageBuffer>& imageBu
     if (!surface->isValid())
         return false;
     OwnPtr<ImageBuffer> image = ImageBuffer::create(surface.release());
+    if (!image)
+        return false;
 
     GraphicsContext* imageContext = image->context();
     ASSERT(imageContext);

Source/platform/graphics/GraphicsContextTest.cpp

@@ -243,6 +243,7 @@ TEST(GraphicsContextTest, trackImageMask)
     context.beginTransparencyLayer(1);
 
     OwnPtr<ImageBuffer> alphaImage = ImageBuffer::create(IntSize(100, 100));
+    EXPECT_FALSE(!alphaImage);
     alphaImage->context()->fillRect(IntRect(0, 0, 100, 100), alpha);
 
     context.setCompositeOperation(CompositeSourceOver);
@@ -280,6 +281,7 @@ TEST(GraphicsContextTest, trackImageMaskWithOpaqueRect)
     context.beginTransparencyLayer(1);
 
     OwnPtr<ImageBuffer> alphaImage = ImageBuffer::create(IntSize(100, 100));
+    EXPECT_FALSE(!alphaImage);
     alphaImage->context()->fillRect(IntRect(0, 0, 100, 100), alpha);
 
     context.setCompositeOperation(CompositeSourceOver);

Source/platform/graphics/RecordingImageBufferSurfaceTest.cpp

@@ -84,6 +84,7 @@ class RecordingImageBufferSurfaceTest : public Test {
         // We create an ImageBuffer in order for the testSurface to be
         // properly initialized with a GraphicsContext
         m_imageBuffer = ImageBuffer::create(testSurface.release());
+        EXPECT_FALSE(!m_imageBuffer);
         m_fakeImageBufferClient = adoptPtr(new FakeImageBufferClient(m_imageBuffer.get()));
         m_imageBuffer->setClient(m_fakeImageBufferClient.get());
     }