Make gfx::Rect class operations consistently mutate the class they are called on.

cc/gl_renderer.cc

 // Copyright 2010 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 "cc/gl_renderer.h"
 
 #include "CCDamageTracker.h"
 #include "CCLayerQuad.h"
@@ skipping 365 matching lines @@
         return scoped_ptr<ScopedTexture>();
     DCHECK(!frame.currentTexture);
 
     // FIXME: Do a single readback for both the surface and replica and cache the filtered results (once filter textures are not reused).
     gfx::Rect deviceRect = gfx::ToEnclosingRect(MathUtil::mapClippedRect(contentsDeviceTransform, sharedGeometryQuad().boundingBox()));
 
     int top, right, bottom, left;
     filters.getOutsets(top, right, bottom, left);
     deviceRect.Inset(-left, -top, -right, -bottom);
 
-    deviceRect = deviceRect.Intersect(frame.currentRenderPass->outputRect());
+    deviceRect.Intersect(frame.currentRenderPass->outputRect());
 
     scoped_ptr<ScopedTexture> deviceBackgroundTexture = ScopedTexture::create(m_resourceProvider);
     if (!getFramebufferTexture(deviceBackgroundTexture.get(), cc::IntRect(deviceRect)))
         return scoped_ptr<ScopedTexture>();
 
     SkBitmap filteredDeviceBackground = applyFilters(this, filters, deviceBackgroundTexture.get());
     if (!filteredDeviceBackground.getTexture())
         return scoped_ptr<ScopedTexture>();
 
     GrTexture* texture = reinterpret_cast<GrTexture*>(filteredDeviceBackground.getTexture());
@@ skipping 534 matching lines @@
 
     setShaderOpacity(quad->opacity(), binding.alphaLocation);
     drawQuadGeometry(frame, quad->quadTransform(), quad->quadRect(), binding.matrixLocation);
 
     GLC(context(), context()->bindTexture(GL_TEXTURE_RECTANGLE_ARB, 0));
 }
 
 void GLRenderer::finishDrawingFrame(DrawingFrame& frame)
 {
     m_currentFramebufferLock.reset();
-    m_swapBufferRect = m_swapBufferRect.Union(gfx::ToEnclosingRect(frame.rootDamageRect));
+    m_swapBufferRect.Union(gfx::ToEnclosingRect(frame.rootDamageRect));
 
     GLC(m_context, m_context->disable(GL_SCISSOR_TEST));
     GLC(m_context, m_context->disable(GL_BLEND));
 }
 
 bool GLRenderer::flippedFramebuffer() const
 {
     return true;
 }
 
@@ skipping 77 matching lines @@
 bool GLRenderer::swapBuffers()
 {
     DCHECK(m_visible);
     DCHECK(!m_isFramebufferDiscarded);
 
     TRACE_EVENT0("cc", "GLRenderer::swapBuffers");
     // We're done! Time to swapbuffers!
 
     if (m_capabilities.usingPartialSwap) {
         // If supported, we can save significant bandwidth by only swapping the damaged/scissored region (clamped to the viewport)
-        m_swapBufferRect = m_swapBufferRect.Intersect(gfx::Rect(gfx::Point(), viewportSize()));
+        m_swapBufferRect.Intersect(gfx::Rect(gfx::Point(), viewportSize()));
         int flippedYPosOfRectBottom = viewportHeight() - m_swapBufferRect.y() - m_swapBufferRect.height();
         m_context->postSubBufferCHROMIUM(m_swapBufferRect.x(), flippedYPosOfRectBottom, m_swapBufferRect.width(), m_swapBufferRect.height());
     } else {
         // Note that currently this has the same effect as swapBuffers; we should
         // consider exposing a different entry point on WebGraphicsContext3D.
         m_context->prepareTexture();
     }
 
     m_swapBufferRect = gfx::Rect();
 
@@ skipping 463 matching lines @@
 
     releaseRenderPassTextures();
 }
 
 bool GLRenderer::isContextLost()
 {
     return (m_context->getGraphicsResetStatusARB() != GL_NO_ERROR);
 }
 
 } // namespace cc