Convert some call sites to use explicit LayoutRect->FloatRect conversion.

Source/core/paint/HTMLCanvasPainter.cpp

 // Copyright 2014 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 "config.h"
 #include "core/paint/HTMLCanvasPainter.h"
 
 #include "core/html/HTMLCanvasElement.h"
 #include "core/layout/LayoutHTMLCanvas.h"
 #include "core/paint/LayoutObjectDrawingRecorder.h"
@@ skipping 16 matching lines @@
 
     LayoutObjectDrawingRecorder drawingRecorder(*context, m_layoutHTMLCanvas, paintInfo.phase, contentRect);
 #if ENABLE(ASSERT)
     // The drawing may be in display list mode or image mode, producing different pictures for the same result.
     drawingRecorder.setUnderInvalidationCheckingMode(DrawingDisplayItem::CheckBitmap);
 #endif
 
     bool clip = !contentRect.contains(paintRect);
     if (clip) {
         context->save();
-        context->clip(contentRect);
+        // TODO(chrishtr): this should be pixel-snapped.
+        context->clip(FloatRect(contentRect));
     }
 
     // FIXME: InterpolationNone should be used if ImageRenderingOptimizeContrast is set.
     // See bug for more details: crbug.com/353716.
     InterpolationQuality interpolationQuality = m_layoutHTMLCanvas.style()->imageRendering() == ImageRenderingOptimizeContrast ? InterpolationLow : CanvasDefaultInterpolationQuality;
     if (m_layoutHTMLCanvas.style()->imageRendering() == ImageRenderingPixelated)
         interpolationQuality = InterpolationNone;
 
     InterpolationQuality previousInterpolationQuality = context->imageInterpolationQuality();
     context->setImageInterpolationQuality(interpolationQuality);
     toHTMLCanvasElement(m_layoutHTMLCanvas.node())->paint(context, paintRect);
     context->setImageInterpolationQuality(previousInterpolationQuality);
 
     if (clip)
         context->restore();
 }
 
 } // namespace blink