Make HTMLCanvasElement::convertLogicalToDevice() clamp float to integer.

Source/core/html/HTMLCanvasElement.cpp

Index: Source/core/html/HTMLCanvasElement.cpp
diff --git a/Source/core/html/HTMLCanvasElement.cpp b/Source/core/html/HTMLCanvasElement.cpp
index 85d444a1d1a0dd25a56f8204dedf14e0b354e1fa..b27a9f6d7520983403bda6c85e98a1f66227b365 100644
--- a/Source/core/html/HTMLCanvasElement.cpp
+++ b/Source/core/html/HTMLCanvasElement.cpp
@@ -406,9 +406,8 @@ PassRefPtr<ImageData> HTMLCanvasElement::getImageData()
 
 IntSize HTMLCanvasElement::convertLogicalToDevice(const IntSize& logicalSize) const
 {
-    float width = ceilf(logicalSize.width() * m_deviceScaleFactor);
-    float height = ceilf(logicalSize.height() * m_deviceScaleFactor);
-    return IntSize(width, height);
+    FloatSize deviceSize = logicalSize * m_deviceScaleFactor;
+    return expandedIntSize(deviceSize);
 }
 
 SecurityOrigin* HTMLCanvasElement::securityOrigin() const