Apply hinting in SkiaTextRenderer::SetFontRenderParams().

ui/gfx/font_render_params_linux.cc

 // 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.
 
 #include "ui/gfx/font_render_params.h"
 
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "ui/gfx/switches.h"
 
@@ skipping 45 matching lines @@
       params->subpixel_rendering = FontRenderParams::SUBPIXEL_RENDERING_VRGB;
       break;
     case FC_RGBA_VBGR:
       params->subpixel_rendering = FontRenderParams::SUBPIXEL_RENDERING_VBGR;
       break;
     default:
       params->subpixel_rendering = FontRenderParams::SUBPIXEL_RENDERING_NONE;
   }
 
 #if defined(OS_LINUX) && !defined(OS_CHROMEOS)
+  // TODO(derat): Get the autohinter setting from FontConfig. Until then,
+  // maintain backward compatibility with what we were doing previously.
+  params->autohinter = renderer;

[Daniel Erat, 2014/07/10 23:46:35]

so this is pretty gross. SkiaTextRenderer wasn't passing the setting through to
SkPaint previously, but android_webview/native/aw_settings.cc and
chrome/browser/renderer_preferences_util.cc _do_ appear to have been passing it
to the renderer. on linux, it'd default to true since that's what we set it to
for chrome os above.

my larger followup change that attaches a FontRenderParams struct to each
gfx::PlatformFont makes us get the autohinter setting from FontConfig, at which
case i'm hopeful this code can go. (although we'll then get the opportunity to
discover how many users have the autohinter turned on in FontConfig
accidentally.)

[msw, 2014/07/11 00:29:09]

Acknowledged.

   const LinuxFontDelegate* delegate = LinuxFontDelegate::instance();
   if (delegate) {
     params->antialiasing = delegate->UseAntialiasing();
     params->hinting = delegate->GetHintingStyle();
     params->subpixel_rendering = delegate->GetSubpixelRenderingStyle();
   }
 #endif
 
   params->subpixel_positioning = SubpixelPositioningRequested(renderer);
 
@@ skipping 20 matching lines @@
     LoadDefaults(&default_params, /* renderer */ true);
   loaded_defaults = true;
   return default_params;
 }
 
 bool GetDefaultWebkitSubpixelPositioning() {
   return SubpixelPositioningRequested(true);
 }
 
 }  // namespace gfx