allow createScalerContext to return null, and then have the GDI backend trigger that if we fail to …

src/core/SkGlyphCache.cpp

 
 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #include "SkGlyphCache.h"
@@ skipping 576 matching lines @@
     /* Release the mutex now, before we create a new entry (which might have
         side-effects like trying to access the cache/mutex (yikes!)
     */
     ac.release();           // release the mutex now
     insideMutex = false;    // can't use globals anymore
 
     // Check if we can create a scaler-context before creating the glyphcache.
     // If not, we may have exhausted OS/font resources, so try purging the
     // cache once and try again.
     {
-        SkScalerContext* ctx = typeface->createScalerContext(desc);
+        // pass true the first time, to notice if the scalercontext failed,
+        // so we can try the purge.
+        SkScalerContext* ctx = typeface->createScalerContext(desc, true);
         if (!ctx) {
             getSharedGlobals().purgeAll();
-            ctx = typeface->createScalerContext(desc);
-            if (!ctx) {
-                sk_throw();
-            }
+            ctx = typeface->createScalerContext(desc, false);
+            SkASSERT(ctx);
         }
         cache = SkNEW_ARGS(SkGlyphCache, (typeface, desc, ctx));
     }
 
 FOUND_IT:
 
     AutoValidate av(cache);
 
     if (proc(cache, context)) {   // stay detached
         if (insideMutex) {
@@ skipping 165 matching lines @@
     return tls ? tls->getFontCacheLimit() : 0;
 }
 
 void SkGraphics::SetTLSFontCacheLimit(size_t bytes) {
     if (0 == bytes) {
         SkGlyphCache_Globals::DeleteTLS();
     } else {
         SkGlyphCache_Globals::GetTLS().setFontCacheLimit(bytes);
     }
 }