Bug 947588. Part 2: Add gfxTextRunFactory::TEXT_HIDE_CONTROL_CHARACTERS to guard usage of IsInvalidControlChar. r=jfkthame

--HG--
extra : rebase_source : 2ce426ebf3ad1643038954bcb18553dec27153c9

gfx/thebes/gfxFont.cpp

@@ -3482,7 +3482,8 @@ gfxFont::ShapeTextWithoutWordCache(gfxContext *aContext,
             aTextRun->SetIsTab(aOffset + i);
         } else if (ch == '\n') {
             aTextRun->SetIsNewline(aOffset + i);
-        } else if (IsInvalidControlChar(ch)) {
+        } else if (IsInvalidControlChar(ch) &&
+            !(aTextRun->GetFlags() & gfxTextRunFactory::TEXT_HIDE_CONTROL_CHARACTERS)) {
             aTextRun->SetMissingGlyph(aOffset + i, ch, this);
         }
         fragStart = i + 1;
@@ -3652,7 +3653,8 @@ gfxFont::SplitAndInitTextRun(gfxContext *aContext,
             aTextRun->SetIsTab(aRunStart + i);
         } else if (ch == '\n') {
             aTextRun->SetIsNewline(aRunStart + i);
-        } else if (IsInvalidControlChar(ch)) {
+        } else if (IsInvalidControlChar(ch) &&
+            !(aTextRun->GetFlags() & gfxTextRunFactory::TEXT_HIDE_CONTROL_CHARACTERS)) {
             aTextRun->SetMissingGlyph(aRunStart + i, ch, this);
         }
 

gfx/thebes/gfxFont.h

@@ -1137,6 +1137,11 @@ public:
          * textruns that have been seen so as to avoid multiple-accounting.
          */
         TEXT_RUN_SIZE_ACCOUNTED      = 0x0200,
+        /**
+         * When set, the textrun should discard control characters instead of
+         * turning them into hexboxes.
+         */
+        TEXT_HIDE_CONTROL_CHARACTERS = 0x0400,
 
         /**
          * nsTextFrameThebes sets these, but they're defined here rather than