Implement direct write fallback proxy

content/browser/renderer_host/dwrite_font_proxy_message_filter_win.cc

Index: content/browser/renderer_host/dwrite_font_proxy_message_filter_win.cc
diff --git a/content/browser/renderer_host/dwrite_font_proxy_message_filter_win.cc b/content/browser/renderer_host/dwrite_font_proxy_message_filter_win.cc
index 6d16572b4fe3eda12e64a096b438e0f0bde20e2a..b3d93b745a1fb291a7b65c518fc5f7760ffe21be 100644
--- a/content/browser/renderer_host/dwrite_font_proxy_message_filter_win.cc
+++ b/content/browser/renderer_host/dwrite_font_proxy_message_filter_win.cc
@@ -20,6 +20,7 @@
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "content/common/dwrite_font_proxy_messages.h"
+#include "content/common/dwrite_text_analysis_source_win.h"
 #include "ipc/ipc_message_macros.h"
 #include "ui/gfx/win/direct_write.h"
 
@@ -90,6 +91,7 @@ bool DWriteFontProxyMessageFilter::OnMessageReceived(
     IPC_MESSAGE_HANDLER(DWriteFontProxyMsg_GetFamilyCount, OnGetFamilyCount)
     IPC_MESSAGE_HANDLER(DWriteFontProxyMsg_GetFamilyNames, OnGetFamilyNames)
     IPC_MESSAGE_HANDLER(DWriteFontProxyMsg_GetFontFiles, OnGetFontFiles)
+    IPC_MESSAGE_HANDLER(DWriteFontProxyMsg_MapCharacters, OnMapCharacters)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
   return handled;
@@ -223,6 +225,97 @@ void DWriteFontProxyMessageFilter::OnGetFontFiles(
   file_paths->assign(path_set.begin(), path_set.end());
 }
 
+void DWriteFontProxyMessageFilter::OnMapCharacters(
+    const base::string16& text,
+    const DWriteFontStyle& font_style,
+    const base::string16& locale_name,
+    uint32_t reading_direction,
+    const base::string16& base_family_name,
+    MapCharactersResult* result) {
+  InitializeDirectWrite();
+  result->family_index = UINT32_MAX;
+  result->mapped_length = text.length();
+  if (factory2_ == nullptr || collection_ == nullptr)
+    return;
+  if (font_fallback_ == nullptr) {
+    if (!SUCCEEDED(factory2_->GetSystemFontFallback(&font_fallback_)))

[ananta, 2016/04/12 23:44:39]

Please change to if (FAILED here and everywhere in this file. 

[Ilya Kulshin, 2016/04/13 01:33:28]

Done.

+      return;
+  }
+
+  UINT32 length;
+  mswr::ComPtr<IDWriteFont> mapped_font;
+
+  mswr::ComPtr<IDWriteNumberSubstitution> number_substitution;
+  if (!SUCCEEDED(factory2_->CreateNumberSubstitution(
+          DWRITE_NUMBER_SUBSTITUTION_METHOD_NONE, locale_name.c_str(),
+          TRUE /* ignoreUserOverride */, &number_substitution))) {
+    DCHECK(false);
+    return;
+  }
+  mswr::ComPtr<IDWriteTextAnalysisSource> analysis_source;
+  if (!SUCCEEDED(mswr::MakeAndInitialize<TextAnalysisSource>(
+          &analysis_source, text, locale_name, number_substitution.Get(),
+          static_cast<DWRITE_READING_DIRECTION>(reading_direction)))) {
+    DCHECK(false);
+    return;
+  }
+
+  if (!SUCCEEDED(font_fallback_->MapCharacters(
+          analysis_source.Get(), 0, text.length(), collection_.Get(),
+          base_family_name.c_str(),
+          static_cast<DWRITE_FONT_WEIGHT>(font_style.font_weight),
+          static_cast<DWRITE_FONT_STYLE>(font_style.font_slant),
+          static_cast<DWRITE_FONT_STRETCH>(font_style.font_stretch), &length,
+          &mapped_font, &result->scale))) {
+    DCHECK(false);
+    return;
+  }
+
+  result->mapped_length = length;
+  if (mapped_font == nullptr)
+    return;
+
+  mswr::ComPtr<IDWriteFontFamily> mapped_family;
+  if (!SUCCEEDED(mapped_font->GetFontFamily(&mapped_family))) {
+    DCHECK(false);
+    return;
+  }
+  mswr::ComPtr<IDWriteLocalizedStrings> family_names;
+  if (!SUCCEEDED(mapped_family->GetFamilyNames(&family_names))) {
+    DCHECK(false);
+    return;
+  }
+
+  std::vector<base::char16> name;
+  size_t name_count = family_names->GetCount();
+  for (size_t name_index = 0; name_index < name_count; name_index++) {
+    UINT32 name_length = 0;
+    if (!SUCCEEDED(family_names->GetStringLength(name_index, &name_length)))
+      continue;  // Keep trying other names
+
+    ++name_length;  // Reserve space for the null terminator.
+    name.resize(name_length);
+    if (!SUCCEEDED(
+            family_names->GetString(name_index, name.data(), name_length)))
+      continue;
+    UINT32 index = UINT32_MAX;
+    BOOL exists = false;
+    if (!SUCCEEDED(collection_->FindFamilyName(name.data(), &index, &exists)) ||
+        !exists)
+      continue;
+
+    // Found a matching family!
+    result->family_index = index;
+    result->family_name = name.data();
+    return;
+  }
+  // Could not find a matching family
+  // TODO(kulshin): log UMA that we matched a font, but could not locate the
+  // family
+  DCHECK_EQ(result->family_index, UINT32_MAX);
+  DCHECK_GT(result->mapped_length, 0u);
+}
+
 void DWriteFontProxyMessageFilter::InitializeDirectWrite() {
   DCHECK_CURRENTLY_ON(BrowserThread::FILE);
   if (direct_write_initialized_)
@@ -237,6 +330,10 @@ void DWriteFontProxyMessageFilter::InitializeDirectWrite() {
     return;
   }
 
+  // QueryInterface for IDWriteFactory2. It's ok for this to fail if we are
+  // running an older version of DirectWrite (earlier than Win8.1).
+  factory.As<IDWriteFactory2>(&factory2_);
+
   HRESULT hr = factory->GetSystemFontCollection(&collection_);
   DCHECK(SUCCEEDED(hr));
 }