Remove parts of //cc we aren't using

cc/resources/raster_source_helper.cc

-// 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 "cc/resources/raster_source_helper.h"
-
-#include "base/trace_event/trace_event.h"
-#include "cc/debug/debug_colors.h"
-#include "third_party/skia/include/core/SkCanvas.h"
-#include "ui/gfx/geometry/rect_conversions.h"
-#include "ui/gfx/skia_util.h"
-
-namespace cc {
-
-void RasterSourceHelper::PrepareForPlaybackToCanvas(
-    SkCanvas* canvas,
-    const gfx::Rect& canvas_rect,
-    const gfx::Rect& source_rect,
-    float contents_scale,
-    SkColor background_color,
-    bool clear_canvas_with_debug_color,
-    bool requires_clear) {
-  canvas->discard();
-  if (clear_canvas_with_debug_color) {
-    // Any non-painted areas in the content bounds will be left in this color.
-    canvas->clear(DebugColors::NonPaintedFillColor());
-  }
-
-  // If this raster source has opaque contents, it is guaranteeing that it will
-  // draw an opaque rect the size of the layer.  If it is not, then we must
-  // clear this canvas ourselves.
-  if (requires_clear) {
-    TRACE_EVENT_INSTANT0("cc", "SkCanvas::clear", TRACE_EVENT_SCOPE_THREAD);
-    // Clearing is about ~4x faster than drawing a rect even if the content
-    // isn't covering a majority of the canvas.
-    canvas->clear(SK_ColorTRANSPARENT);
-  } else {
-    // Even if completely covered, for rasterizations that touch the edge of the
-    // layer, we also need to raster the background color underneath the last
-    // texel (since the recording won't cover it) and outside the last texel
-    // (due to linear filtering when using this texture).
-    gfx::Rect content_rect =
-        gfx::ToEnclosingRect(gfx::ScaleRect(source_rect, contents_scale));
-
-    // The final texel of content may only be partially covered by a
-    // rasterization; this rect represents the content rect that is fully
-    // covered by content.
-    gfx::Rect deflated_content_rect = content_rect;
-    deflated_content_rect.Inset(0, 0, 1, 1);
-    if (!deflated_content_rect.Contains(canvas_rect)) {
-      if (clear_canvas_with_debug_color) {
-        // Any non-painted areas outside of the content bounds are left in
-        // this color.  If this is seen then it means that cc neglected to
-        // rerasterize a tile that used to intersect with the content rect
-        // after the content bounds grew.
-        canvas->save();
-        canvas->translate(-canvas_rect.x(), -canvas_rect.y());
-        canvas->clipRect(gfx::RectToSkRect(content_rect),
-                         SkRegion::kDifference_Op);
-        canvas->drawColor(DebugColors::MissingResizeInvalidations(),
-                          SkXfermode::kSrc_Mode);
-        canvas->restore();
-      }
-
-      // Drawing at most 2 x 2 x (canvas width + canvas height) texels is 2-3X
-      // faster than clearing, so special case this.
-      canvas->save();
-      canvas->translate(-canvas_rect.x(), -canvas_rect.y());
-      gfx::Rect inflated_content_rect = content_rect;
-      inflated_content_rect.Inset(0, 0, -1, -1);
-      canvas->clipRect(gfx::RectToSkRect(inflated_content_rect),
-                       SkRegion::kReplace_Op);
-      canvas->clipRect(gfx::RectToSkRect(deflated_content_rect),
-                       SkRegion::kDifference_Op);
-      canvas->drawColor(background_color, SkXfermode::kSrc_Mode);
-      canvas->restore();
-    }
-  }
-}
-
-}  // namespace cc