Add support for enabling DirectWrite for font rendering in Chrome UI.

This is enabled if Harf Buzz text rendering is enabled and if the enable-directwrite-for-ui switch
is passed in the command line.

To enable DirectWrite we use the SkFontMgr_New_DirectWrite function in skia which sets up skia to use
DirectWrite for font rendering. This is done once during startup.

BUG=389649

Review URL: https://codereview.chromium.org/655613003

Cr-Commit-Position: refs/heads/master@{#299612}

1 files changed, 17 insertions, 0 deletions

diff --git a/content/browser/browser_main_runner.cc b/content/browser/browser_main_runner.cc
index 80869f3..5df5d99 100644
--- a/content/browser/browser_main_runner.cc
+++ b/content/browser/browser_main_runner.cc
@@ -24,7 +24,12 @@
 #include "base/win/windows_version.h"
 #include "net/cert/sha256_legacy_support_win.h"
 #include "sandbox/win/src/sidestep/preamble_patcher.h"
+#include "skia/ext/fontmgr_default_win.h"
+#include "third_party/skia/include/ports/SkFontMgr.h"
+#include "third_party/skia/include/ports/SkTypeface_win.h"
 #include "ui/base/win/scoped_ole_initializer.h"
+#include "ui/gfx/switches.h"
+#include "ui/gfx/win/direct_write.h"
 #endif
 
 bool g_exited_main_message_loop = false;
@@ -110,6 +115,16 @@ void InstallSha256LegacyHooks() {
 #endif  // _WIN64
 }
 
+void MaybeEnableDirectWriteFontRendering() {
+  if (gfx::win::ShouldUseDirectWrite() &&
+      CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kEnableDirectWriteForUI) &&
+      CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kEnableHarfBuzzRenderText)) {
+    SetDefaultSkiaFactory(SkFontMgr_New_DirectWrite(NULL));
+  }
+}
+
 }  // namespace
 
 #endif  // OS_WIN
@@ -162,6 +177,8 @@ class BrowserMainRunnerImpl : public BrowserMainRunner {
       // (Text Services Framework) module can interact with the message pump
       // on Windows 8 Metro mode.
       ole_initializer_.reset(new ui::ScopedOleInitializer);
+      // Enable DirectWrite font rendering if needed.
+      MaybeEnableDirectWriteFontRendering();
 #endif  // OS_WIN
 
       main_loop_.reset(new BrowserMainLoop(parameters));