Fixed bookkeeping bug in management of dimensions of mailbox's texture.

Source/web/tests/DrawingBufferTest.cpp

Index: Source/web/tests/DrawingBufferTest.cpp
diff --git a/Source/web/tests/DrawingBufferTest.cpp b/Source/web/tests/DrawingBufferTest.cpp
index 2b72d40ff993e5c954ab0daa6ba6519ee2636e43..dc8bd6971d0d2d6359001fb7fd4296ba5db5082a 100644
--- a/Source/web/tests/DrawingBufferTest.cpp
+++ b/Source/web/tests/DrawingBufferTest.cpp
@@ -34,6 +34,7 @@
 
 #include "platform/graphics/GraphicsContext3D.h"
 #include "public/platform/Platform.h"
+#include "public/platform/WebExternalTextureMailbox.h"
 #include "web/tests/MockWebGraphicsContext3D.h"
 #include "wtf/RefPtr.h"
 
@@ -53,6 +54,56 @@ public:
     IntSize oldestContextSize() { return IntSize(); }
 };
 
+class WebGraphicsContext3DForTests : public MockWebGraphicsContext3D {
+public:
+    WebGraphicsContext3DForTests()
+        : MockWebGraphicsContext3D()
+        , m_boundTexture(0)
+        , m_currentMailboxByte(0) { }
+
+    virtual void bindTexture(WGC3Denum target, WebGLId texture)
+    {
+        if (target == GraphicsContext3D::TEXTURE_2D) {
+            m_boundTexture = texture;
+        }
+    }
+
+    virtual void texImage2D(WGC3Denum target, WGC3Dint level, WGC3Denum internalformat, WGC3Dsizei width, WGC3Dsizei height, WGC3Dint border, WGC3Denum format, WGC3Denum type, const void* pixels)
+    {
+        if (target == GraphicsContext3D::TEXTURE_2D && !level) {
+            m_textureSizes.set(m_boundTexture, IntSize(width, height));
+        }
+    }
+
+    virtual void genMailboxCHROMIUM(WGC3Dbyte* mailbox)
+    {
+        ++m_currentMailboxByte;
+        WebExternalTextureMailbox temp;
+        memset(mailbox, m_currentMailboxByte, sizeof(temp.name));
+    }
+
+    virtual void produceTextureCHROMIUM(WGC3Denum target, const WGC3Dbyte* mailbox)
+    {
+        ASSERT_EQ(target, GraphicsContext3D::TEXTURE_2D);
+        m_mostRecentlyProducedSize = m_textureSizes.get(m_boundTexture);
+    }
+
+    IntSize mostRecentlyProducedSize()
+    {
+        return m_mostRecentlyProducedSize;
+    }
+
+private:
+    WebGLId m_boundTexture;
+    HashMap<WebGLId, IntSize> m_textureSizes;
+    WGC3Dbyte m_currentMailboxByte;
+    IntSize m_mostRecentlyProducedSize;
+};
+
+static const int initialWidth = 100;
+static const int initialHeight = 100;
+static const int alternateHeight = 50;
+
 } // namespace
 
 class DrawingBufferTest : public Test {
@@ -60,9 +111,13 @@ protected:
     virtual void SetUp()
     {
         RefPtr<FakeContextEvictionManager> contextEvictionManager = adoptRef(new FakeContextEvictionManager());
-        RefPtr<GraphicsContext3D> context = GraphicsContext3D::createGraphicsContextFromWebContext(adoptPtr(new MockWebGraphicsContext3D));
-        const IntSize size(100, 100);
-        m_drawingBuffer = DrawingBuffer::create(context.get(), size, DrawingBuffer::Discard, contextEvictionManager.release());
+        RefPtr<GraphicsContext3D> context = GraphicsContext3D::createGraphicsContextFromWebContext(adoptPtr(new WebGraphicsContext3DForTests));
+        m_drawingBuffer = DrawingBuffer::create(context.get(), IntSize(initialWidth, initialHeight), DrawingBuffer::Discard, contextEvictionManager.release());
+    }
+
+    WebGraphicsContext3DForTests* webContext()
+    {
+        return static_cast<WebGraphicsContext3DForTests*>(m_drawingBuffer->context());
     }
 
     RefPtr<DrawingBuffer> m_drawingBuffer;
@@ -80,4 +135,41 @@ TEST_F(DrawingBufferTest, verifyNoNewBuffersAfterContextLostWithMailboxes)
     EXPECT_FALSE(m_drawingBuffer->prepareMailbox(&mailbox, 0));
 }
 
+TEST_F(DrawingBufferTest, verifyResizingProperlyAffectsMailboxes)
+{
+    blink::WebExternalTextureMailbox mailbox;
+
+    IntSize initialSize(initialWidth, initialHeight);
+    IntSize alternateSize(initialWidth, alternateHeight);
+
+    // Produce one mailbox at size 100x100.
+    m_drawingBuffer->markContentsChanged();
+    EXPECT_TRUE(m_drawingBuffer->prepareMailbox(&mailbox, 0));
+    EXPECT_EQ(initialSize, webContext()->mostRecentlyProducedSize());
+
+    // Resize to 100x50.
+    m_drawingBuffer->reset(IntSize(initialWidth, alternateHeight));
+    m_drawingBuffer->mailboxReleased(mailbox);
+
+    // Produce a mailbox at this size.
+    m_drawingBuffer->markContentsChanged();
+    EXPECT_TRUE(m_drawingBuffer->prepareMailbox(&mailbox, 0));
+    EXPECT_EQ(alternateSize, webContext()->mostRecentlyProducedSize());
+
+    // Reset to initial size.
+    m_drawingBuffer->reset(IntSize(initialWidth, initialHeight));
+    m_drawingBuffer->mailboxReleased(mailbox);
+
+    // Prepare another mailbox and verify that it's the correct size.
+    m_drawingBuffer->markContentsChanged();
+    EXPECT_TRUE(m_drawingBuffer->prepareMailbox(&mailbox, 0));
+    EXPECT_EQ(initialSize, webContext()->mostRecentlyProducedSize());
+
+    // Prepare one final mailbox and verify that it's the correct size.
+    m_drawingBuffer->mailboxReleased(mailbox);
+    m_drawingBuffer->markContentsChanged();
+    EXPECT_TRUE(m_drawingBuffer->prepareMailbox(&mailbox, 0));
+    EXPECT_EQ(initialSize, webContext()->mostRecentlyProducedSize());
+}
+
 } // namespace