[vr] Bail on unhandled code points.

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>
 
@@ skipping 144 matching lines @@
 }
 
 bool UiTexture::IsRTL() {
   return base::i18n::IsRTL();
 }
 
 gfx::FontList UiTexture::GetDefaultFontList(int size) {
   return gfx::FontList(gfx::Font(kDefaultFontFamily, size));
 }
 
+bool UiTexture::CheckFontList(int size, base::string16 text) {

[cjgrant, 2017/05/25 17:47:24]

I thought this change would use the existing character lookup, but just report a
failure, so the caller can optionally bail.  I ask because I thought these
lookups were slow...

[Ian Vollick, 2017/05/26 03:48:09]

It's true, they are slow. I may be misunderstanding what you mean by existing
character lookup -- are you suggesting I instrument GetFontList below? (I
started by doing that, then learned that the URL bar texture doesn't use
GetFontList, in uses GetDefaultFontList above, which isn't as easy to piggy back
upon).

+  gfx::Font default_font(kDefaultFontFamily, size);
+
+  // TODO(acondor): Query BrowserProcess to obtain the application locale.
+  for (UChar32 c : CollectDifferentChars(text)) {
+    std::string name = GetFallbackFontNameForChar(default_font, c, "");

[cjgrant, 2017/05/25 17:47:24]

Up to you, but probably don't need "name";
if (GetFallbackl().empty()) {
would be just as easy to read.

[Ian Vollick, 2017/05/26 03:48:09]

The code ended up being structured differently, and I don't think this comment
applies anymore.

+    if (name.empty()) {
+      // This happens a lot?

[acondor_, 2017/05/25 15:51:42]

GetFallbackFontNameForChar assumes that the default_font is not a fallback, so
it wouldn't return it. Now, we might want to change this function to report
whether the empty string was because it was supported by the default font or
because it didn't find any fallback.

[cjgrant, 2017/05/25 17:47:24]

The comment and print look like leftover debug?

[Ian Vollick, 2017/05/26 03:48:09]

Yeah, as we chatted about offline, this was in a WIP state (the unit tests,
too).

+      LOG(ERROR) << "couldn't handle this char: " << c;
+      return false;
+    }
+  }
+  return true;
+}
+
 gfx::FontList UiTexture::GetFontList(int size, base::string16 text) {
   gfx::Font default_font(kDefaultFontFamily, size);
   std::vector<gfx::Font> fonts{default_font};
 
   std::set<std::string> names;
   // TODO(acondor): Query BrowserProcess to obtain the application locale.
   for (UChar32 c : CollectDifferentChars(text)) {
     std::string name = GetFallbackFontNameForChar(default_font, c, "");
     if (!name.empty())
       names.insert(name);
   }
   for (const auto& name : names)
     fonts.push_back(gfx::Font(name, size));
   return gfx::FontList(fonts);
 }
 
 }  // namespace vr_shell