Implement API for accessing fonts installed locally on the system.

third_party/WebKit/Source/core/css/FontFaceSet.cpp

Index: third_party/WebKit/Source/core/css/FontFaceSet.cpp
diff --git a/third_party/WebKit/Source/core/css/FontFaceSet.cpp b/third_party/WebKit/Source/core/css/FontFaceSet.cpp
index e0c6c7f57d5db04227694db60bbc390c76f22fb3..3de2ed2322c448c2cf6620d60fd22ea4a043bfb8 100644
--- a/third_party/WebKit/Source/core/css/FontFaceSet.cpp
+++ b/third_party/WebKit/Source/core/css/FontFaceSet.cpp
@@ -25,13 +25,16 @@
 
 #include "core/css/FontFaceSet.h"
 
+#include "bindings/core/v8/CallbackPromiseAdapter.h"
 #include "bindings/core/v8/Dictionary.h"
 #include "bindings/core/v8/ScriptPromiseResolver.h"
 #include "bindings/core/v8/ScriptState.h"
 #include "core/css/CSSFontSelector.h"
 #include "core/css/CSSSegmentedFontFace.h"
 #include "core/css/FontFaceCache.h"
+#include "core/css/FontFaceDescriptors.h"
 #include "core/css/FontFaceSetLoadEvent.h"
+#include "core/css/LocalFontFace.h"
 #include "core/css/StylePropertySet.h"
 #include "core/css/parser/CSSParser.h"
 #include "core/css/resolver/StyleResolver.h"
@@ -41,6 +44,9 @@
 #include "core/frame/LocalFrame.h"
 #include "core/style/StyleInheritedData.h"
 #include "platform/Histogram.h"
+#include "public/platform/Platform.h"
+#include "public/platform/modules/font_access/WebFontAccess.h"
+#include "public/platform/modules/font_access/WebFontAccessDescription.h"
 
 namespace blink {
 
@@ -536,6 +542,54 @@ bool FontFaceSet::IterationSource::next(ScriptState*, RefPtrWillBeMember<FontFac
     return true;
 }
 
+class FontAccessDescriptionCallback final : public FontAccessCallbacks {
+public:
+    FontAccessDescriptionCallback(ScriptPromiseResolver* resolver, ScriptState* scriptState)
+        : m_resolver(resolver)
+        , m_executionContext(scriptState->executionContext())
+    {
+    }
+
+    void onSuccess(WebPassOwnPtr<WebVector<WebFontAccessDescription>> description) override
+    {
+        WillBeHeapVector<RefPtrWillBeMember<FontFace>> fonts;
+        OwnPtr<WebVector<WebFontAccessDescription>> webFonts = description.release();
+        blink::FontFaceDescriptors faceDecsription;
+        for (const auto webFont : *webFonts) {
+            StringOrArrayBufferOrArrayBufferView cssString;
+            StringBuilder result;
+            result.append("local('");
+            result.append(webFont.fullName);
+            result.append(')');
+            cssString.setString(result.toString());
+            RefPtrWillBeMember<LocalFontFace> ff = LocalFontFace::create(m_executionContext.get(), webFont.family, webFont.style, webFont.fullName, cssString, faceDecsription);
+            fonts.append(ff);
+        }
+
+        m_resolver->resolve(fonts);
+    }
+    void onError() override
+    {
+    }
+
+private:
+    Persistent<ScriptPromiseResolver> m_resolver;
+    RefPtrWillBePersistent<ExecutionContext> m_executionContext;
+};
+
+ScriptPromise FontFaceSet::systemFonts(ScriptState* scriptState)
+{
+    WebFontAccess* webfontaccess = Platform::current()->fontAccess();
+    if (!webfontaccess)
+        return ScriptPromise::rejectWithDOMException(scriptState, DOMException::create(NotSupportedError));
+
+    ScriptPromiseResolver* resolver = ScriptPromiseResolver::create(scriptState);
+    ScriptPromise promise = resolver->promise();
+
+    webfontaccess->getFonts(new FontAccessDescriptionCallback(resolver, scriptState));
+    return promise;
+}
+
 DEFINE_TRACE(FontFaceSet)
 {
 #if ENABLE(OILPAN)