Rendering text on insecure-site warnings for WebVR

chrome/browser/android/vr_shell/textures/ui_texture.cc

 // Copyright 2017 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 "chrome/browser/android/vr_shell/textures/ui_texture.h"
 
+#include <set>
 #include <string>
 #include <vector>
 
+#include "base/i18n/char_iterator.h"
 #include "base/memory/ptr_util.h"
 #include "base/strings/string_util.h"
+#include "chrome/browser/browser_process.h"
 #include "third_party/skia/include/core/SkCanvas.h"
+#include "third_party/skia/include/ports/SkFontMgr.h"
 #include "ui/gfx/canvas.h"
+#include "ui/gfx/font_list.h"
 #include "ui/gl/gl_bindings.h"
 
 namespace vr_shell {
 
+namespace {
+constexpr char kDefaultFontFamily[] = "sans-serif";
+}  // namespace
+
 // TODO(acondor): Create non-square textures to reduce memory usage.
 UITexture::UITexture(int texture_handle, int texture_size)
     : texture_handle_(texture_handle),
       texture_size_(texture_size),
       surface_(SkSurface::MakeRasterN32Premul(texture_size_, texture_size_)) {}
 
 UITexture::~UITexture() = default;
 
 void UITexture::DrawAndLayout() {
   cc::SkiaPaintCanvas paint_canvas(surface_->getCanvas());
@@ skipping 11 matching lines @@
 
   glBindTexture(GL_TEXTURE_2D, texture_handle_);
   glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, pixmap.width(), pixmap.height(), 0,
                GL_RGBA, GL_UNSIGNED_BYTE, pixmap.addr());
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 }
 
+gfx::FontList UITexture::GetFontList(int size, base::string16 text) {

[mthiesse, 2017/04/18 21:30:35]

This feels like code that shouldn't be specific to vr_shell. Add a TODO to find
a better location for it?

[acondor_, 2017/04/18 23:48:46]

Added a TODO. It should be gfx::GetFallbackFonts, but it doesn't accept
characters as input. Blink's code for fallback fonts also uses Skia Font
Manager, but it also uses a character to get it. On the other hand,
gfx::GetFallbackFonts uses fontconfig on linux. So, we have to decide if we want
to port this approach to android or stay with Blink's instead.

+  gfx::Font default_font(kDefaultFontFamily, size);
+  std::vector<gfx::Font> fonts{default_font};
+  sk_sp<SkFontMgr> font_mgr(SkFontMgr::RefDefault());
+  std::set<std::string> names;
+  // TODO(acondor): Query BrowserProcess to obtain the application locale.
+  for (base::i18n::UTF16CharIterator it(&text); !it.end(); it.Advance()) {
+    sk_sp<SkTypeface> tf(font_mgr->matchFamilyStyleCharacter(
+        default_font.GetFontName().c_str(), SkFontStyle(), nullptr, 0,
+        it.get()));
+    SkString sk_name;
+    tf->getFamilyName(&sk_name);
+    std::string name(sk_name.c_str());
+    if (name != kDefaultFontFamily)
+      names.insert(name);
+  }
+  for (const auto& name : names)
+    fonts.push_back(gfx::Font(name, size));
+  return gfx::FontList(fonts);
+}
+
 }  // namespace vr_shell