Set the font family for the "system-ui" generic font family on Linux

This patch sets the font family for the "system-ui" generic font family
added in [1] on Linux.

With this change, all platforms use the correct font. On Windows, the
browser already pass menu_font_family_name to the renderer. On Mac and
Android, the render can find the system font without needing the
browser to set.

On Linux and Chrome OS, gfx::Font() calls LinuxFontDelegate to figure
out the current system font. On the default Ubuntu, this resolves to
"sans", which Skia resolves to "DejaVu Sans", or "Arial" in
run-layout-test.

[1] http://crrev.com/2137483004

BUG=654679

Review-Url: https://codereview.chromium.org/2138613002
Cr-Commit-Position: refs/heads/master@{#427262}

content/browser/renderer_host/render_view_host_impl.cc

@@ -113,8 +113,8 @@ using blink::WebPluginAction;
 namespace content {
 namespace {
 
+void GetPlatformSpecificPrefs(RendererPreferences* prefs) {
 #if defined(OS_WIN)
-void GetWindowsSpecificPrefs(RendererPreferences* prefs) {
   NONCLIENTMETRICS_XP metrics = {0};
   base::win::GetNonClientMetrics(&metrics);
 
@@ -146,8 +146,10 @@ void GetWindowsSpecificPrefs(RendererPreferences* prefs) {
       display::win::ScreenWin::GetSystemMetricsInDIP(SM_CYVSCROLL);
   prefs->arrow_bitmap_width_horizontal_scroll_bar_in_dips =
       display::win::ScreenWin::GetSystemMetricsInDIP(SM_CXHSCROLL);
-}
+#elif defined(OS_LINUX)
+  prefs->system_font_family_name = gfx::Font().GetFontName();
 #endif
+}
 
 std::vector<DropData::Metadata> DropDataToMetaData(const DropData& drop_data) {
   std::vector<DropData::Metadata> metadata;
@@ -341,9 +343,7 @@ bool RenderViewHostImpl::CreateRenderView(
   mojom::CreateViewParamsPtr params = mojom::CreateViewParams::New();
   params->renderer_preferences =
       delegate_->GetRendererPrefs(GetProcess()->GetBrowserContext());
-#if defined(OS_WIN)
-  GetWindowsSpecificPrefs(&params->renderer_preferences);
-#endif
+  GetPlatformSpecificPrefs(&params->renderer_preferences);
   params->web_preferences = GetWebkitPreferences();
   params->view_id = GetRoutingID();
   params->main_frame_routing_id = main_frame_routing_id_;
@@ -409,9 +409,7 @@ bool RenderViewHostImpl::IsRenderViewLive() const {
 void RenderViewHostImpl::SyncRendererPrefs() {
   RendererPreferences renderer_preferences =
       delegate_->GetRendererPrefs(GetProcess()->GetBrowserContext());
-#if defined(OS_WIN)
-  GetWindowsSpecificPrefs(&renderer_preferences);
-#endif
+  GetPlatformSpecificPrefs(&renderer_preferences);
   Send(new ViewMsg_SetRendererPrefs(GetRoutingID(), renderer_preferences));
 }
 

content/common/view_messages.h

@@ -245,6 +245,9 @@ IPC_STRUCT_TRAITS_BEGIN(content::RendererPreferences)
   IPC_STRUCT_TRAITS_MEMBER(plugin_fullscreen_allowed)
   IPC_STRUCT_TRAITS_MEMBER(use_video_overlay_for_embedded_encrypted_video)
   IPC_STRUCT_TRAITS_MEMBER(network_contry_iso)
+#if defined(OS_LINUX)
+  IPC_STRUCT_TRAITS_MEMBER(system_font_family_name)
+#endif
 #if defined(OS_WIN)
   IPC_STRUCT_TRAITS_MEMBER(caption_font_family_name)
   IPC_STRUCT_TRAITS_MEMBER(caption_font_height)

content/public/common/renderer_preferences.h

@@ -139,6 +139,10 @@ struct CONTENT_EXPORT RendererPreferences {
   // Country iso of the mobile network for content detection purpose.
   std::string network_contry_iso;
 
+#if defined(OS_LINUX)
+  std::string system_font_family_name;
+#endif
+
 #if defined(OS_WIN)
   // The default system font settings for caption, small caption, menu and
   // status messages. Used only by Windows.

content/renderer/render_view_linux.cc

@@ -69,6 +69,12 @@ void RenderViewImpl::UpdateFontRenderingFromRendererPrefs() {
       prefs.default_font_size <= kMaxDefaultFontSize) {
     WebFontRendering::setDefaultFontSize(prefs.default_font_size);
   }
+#if !defined(OS_ANDROID)
+  if (!prefs.system_font_family_name.empty()) {
+    WebFontRendering::setSystemFontFamily(
+        blink::WebString::fromUTF8(prefs.system_font_family_name));
+  }
+#endif
 }
 
 }  // namespace content

third_party/WebKit/LayoutTests/platform/linux/inspector-protocol/layout-fonts/generic-system-ui-expected.txt

 This text should use the system font.
 #system-ui:
-"Times New Roman" : 37
+"Arial" : 37
 
 This text should use the system font.
 #system-ui-20pt:
-"Times New Roman" : 37
+"Arial" : 37
 
 

third_party/WebKit/Source/platform/fonts/FontCache.h

@@ -120,8 +120,8 @@ class PLATFORM_EXPORT FontCache {
 #else
   static const AtomicString& legacySystemFontFamily();
 #endif
-#if OS(LINUX)
-  static void setSystemFontFamily(const char*);
+#if OS(LINUX) || OS(ANDROID)
+  static void setSystemFontFamily(const AtomicString&);
 #endif
 
 #if OS(WIN)

third_party/WebKit/Source/platform/fonts/android/FontCacheAndroid.cpp

@@ -60,6 +60,9 @@ const AtomicString& FontCache::systemFontFamily() {
   return systemFontFamily;
 }
 
+// static
+void FontCache::setSystemFontFamily(const AtomicString&) {}
+
 PassRefPtr<SimpleFontData> FontCache::fallbackFontForCharacter(
     const FontDescription& fontDescription,
     UChar32 c,

third_party/WebKit/Source/platform/fonts/linux/FontCacheLinux.cpp

@@ -54,8 +54,8 @@ const AtomicString& FontCache::systemFontFamily() {
 }
 
 // static
-void FontCache::setSystemFontFamily(const char* familyName) {
-  DCHECK(familyName && *familyName);
+void FontCache::setSystemFontFamily(const AtomicString& familyName) {
+  DCHECK(!familyName.isEmpty());
   mutableSystemFontFamily() = familyName;
 }
 

third_party/WebKit/Source/web/linux/WebFontRendering.cpp

@@ -81,4 +81,9 @@ void WebFontRendering::setDefaultFontSize(int size) {
   LayoutThemeFontProvider::setDefaultFontSize(size);
 }
 
+// static
+void WebFontRendering::setSystemFontFamily(const WebString& name) {
+  FontCache::setSystemFontFamily(name);
+}
+
 }  // namespace blink

third_party/WebKit/public/web/linux/WebFontRendering.h

@@ -32,6 +32,7 @@
 #define WebFontRendering_h
 
 #include "../../platform/WebCommon.h"
+#include "../../platform/WebString.h"
 #include <SkFontMgr.h>
 #include <SkPaint.h>
 
@@ -49,6 +50,7 @@ class WebFontRendering {
   BLINK_EXPORT static void setSubpixelRendering(bool);
   BLINK_EXPORT static void setSubpixelPositioning(bool);
   BLINK_EXPORT static void setDefaultFontSize(int);
+  BLINK_EXPORT static void setSystemFontFamily(const WebString&);
 };
 
 }  // namespace blink