ui: Remove use of bitmaps when painting tab backgrounds.

chrome/browser/ui/views/tabs/tab.h

 // Copyright (c) 2012 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.
 
 #ifndef CHROME_BROWSER_UI_VIEWS_TABS_TAB_H_
 #define CHROME_BROWSER_UI_VIEWS_TABS_TAB_H_
 
 #include <list>
 #include <memory>
 #include <string>
 
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
+#include "cc/paint/paint_record.h"
 #include "chrome/browser/ui/views/tabs/tab_renderer_data.h"
 #include "ui/base/layout.h"
 #include "ui/gfx/animation/animation_delegate.h"
 #include "ui/gfx/geometry/point.h"
 #include "ui/gfx/image/image_skia.h"
 #include "ui/gfx/paint_throbber.h"
 #include "ui/views/context_menu_controller.h"
 #include "ui/views/controls/button/button.h"
 #include "ui/views/controls/glow_hover_controller.h"
 #include "ui/views/masked_targeter_delegate.h"
@@ skipping 203 matching lines @@
   // Paints with the normal tab style.  If |clip| is non-empty, the tab border
   // should be clipped against it.
   void PaintTab(gfx::Canvas* canvas, const gfx::Path& clip);
 
   // Paints the background of an inactive tab.
   void PaintInactiveTabBackground(gfx::Canvas* canvas, const gfx::Path& clip);
 
   // Paints a tab background using the image defined by |fill_id| at the
   // provided offset. If |fill_id| is 0, it will fall back to using the solid
   // color defined by the theme provider and ignore the offset.
-  void PaintTabBackgroundUsingFillId(gfx::Canvas* fill_canvas,
-                                     gfx::Canvas* stroke_canvas,
-                                     bool is_active,
-                                     int fill_id,
-                                     int y_offset);
+  void PaintTabBackground(gfx::Canvas* canvas,
+                          bool active,
+                          int fill_id,
+                          int y_offset,
+                          const gfx::Path* clip);
+
+  // Helper methods for PaintTabBackground.
+  void PaintTabBackgroundFill(gfx::Canvas* canvas,
+                              const gfx::Path& fill_path,
+                              bool active,
+                              bool hover,
+                              SkColor active_color,
+                              SkColor inactive_color,
+                              int fill_id,
+                              int y_offset);
+  void PaintTabBackgroundStroke(gfx::Canvas* canvas,
+                                const gfx::Path& fill_path,
+                                bool active);
 
   // Paints the pinned tab title changed indicator and |favicon_|. |favicon_|
   // may be null. |favicon_draw_bounds| is |favicon_bounds_| adjusted for rtl
   // and clipped to the bounds of the tab.
   void PaintPinnedTabTitleChangedIndicatorAndIcon(
       gfx::Canvas* canvas,
       const gfx::Rect& favicon_draw_bounds);
 
   // Paints the favicon, mirrored for RTL if needed.
   void PaintIcon(gfx::Canvas* canvas);
@@ skipping 95 matching lines @@
   bool showing_close_button_;
 
   // The current color of the alert indicator and close button icons.
   SkColor button_color_;
 
   // The favicon for the tab. This might be the sad tab icon or a copy of
   // data().favicon and may be modified for theming. It is created on demand
   // and thus may be null.
   gfx::ImageSkia favicon_;
 
+  struct BackgroundCache {

[Peter Kasting, 2017/04/07 00:59:20]

Nit: I think the Google style guide requests that structs go atop the section,
even though I understand why you defined it down here next to the use of the
type.

[danakj, 2017/04/07 19:10:49]

yeh.. that seems unfortunate here. The guide says "Within each section,
generally prefer grouping similar kinds of declarations together" but its not
strictly always. I'd prefer to keep this where it is if you're okay with that. I
think it would reduce readability to move it.

[Peter Kasting, 2017/04/07 23:34:03]

It's OK to keep it here.  It'd be even better to move it into the .cc file
somehow, but not at the expense of having to create unique_ptrs for this type
for the members and do heap allocations.

+    BackgroundCache();
+    ~BackgroundCache();
+
+    // Parameters used to construct the PaintRecords.
+    float scale = 0.f;
+    gfx::Size size;
+    SkColor active_color;

[Peter Kasting, 2017/04/07 00:59:20]

Nit: If you're going to init |scale| in the declaration list I'd also init these
colors (which are really BTs as well).

[danakj, 2017/04/07 19:10:49]

Right, don't want to compare uninit things, even tho scale is enough to cause
the initial cache to not be value.

+    SkColor inactive_color;
+
+    // The PaintRecords being cached based on the above parameters.
+    sk_sp<cc::PaintRecord> fill_record;
+    sk_sp<cc::PaintRecord> stroke_record;
+  };
+
+  BackgroundCache background_active_cache_;
+  BackgroundCache background_inactive_cache_;
+
   DISALLOW_COPY_AND_ASSIGN(Tab);
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_TABS_TAB_H_