Bug 1485425 - Protect more DWrite API usage in gfxDWriteFontList::ReadFaceNamesForFamily with MOZ_SEH_TRY/EXCEPT. r=lsalzman

The majority of the crashes I looked at here are happening under ReadFaceNamesForFamily.
We already have an SEH guard aronud part of the method, but it doesn't cover all the potentially
problematic DWrite calls, so this patch moves more of the code inside the try/except block
to attempt to handle exceptions safely.x

Differential Revision: https://phabricator.services.mozilla.com/D165524

gfx/thebes/gfxDWriteFontList.cpp

@@ -1437,34 +1437,34 @@ void gfxDWriteFontList::ReadFaceNamesForFamily(
   nsAutoCString familyName(aFamily->DisplayName().AsString(list));
   nsAutoCString key(aFamily->Key().AsString(list));
 
-  // Read PS-names and fullnames of the faces, and any alternate family names
-  // (either localizations or legacy subfamily names)
-  for (unsigned i = 0; i < aFamily->NumFaces(); ++i) {
-    auto face = static_cast<fontlist::Face*>(facePtrs[i].ToPtr(list));
-    if (!face) {
-      continue;
-    }
-    RefPtr<IDWriteFont> dwFont;
-    if (FAILED(family->GetFont(face->mIndex, getter_AddRefs(dwFont)))) {
-      continue;
-    }
-    RefPtr<IDWriteFontFace> dwFontFace;
-    if (FAILED(dwFont->CreateFontFace(getter_AddRefs(dwFontFace)))) {
-      continue;
-    }
+  MOZ_SEH_TRY {
+    // Read PS-names and fullnames of the faces, and any alternate family names
+    // (either localizations or legacy subfamily names)
+    for (unsigned i = 0; i < aFamily->NumFaces(); ++i) {
+      auto face = static_cast<fontlist::Face*>(facePtrs[i].ToPtr(list));
+      if (!face) {
+        continue;
+      }
+      RefPtr<IDWriteFont> dwFont;
+      if (FAILED(family->GetFont(face->mIndex, getter_AddRefs(dwFont)))) {
+        continue;
+      }
+      RefPtr<IDWriteFontFace> dwFontFace;
+      if (FAILED(dwFont->CreateFontFace(getter_AddRefs(dwFontFace)))) {
+        continue;
+      }
 
-    const char* data;
-    UINT32 size;
-    void* context;
-    BOOL exists;
-    if (FAILED(dwFontFace->TryGetFontTable(
-            NativeEndian::swapToBigEndian(TRUETYPE_TAG('n', 'a', 'm', 'e')),
-            (const void**)&data, &size, &context, &exists)) ||
-        !exists) {
-      continue;
-    }
+      const char* data;
+      UINT32 size;
+      void* context;
+      BOOL exists;
+      if (FAILED(dwFontFace->TryGetFontTable(
+              NativeEndian::swapToBigEndian(TRUETYPE_TAG('n', 'a', 'm', 'e')),
+              (const void**)&data, &size, &context, &exists)) ||
+          !exists) {
+        continue;
+      }
 
-    MOZ_SEH_TRY {
       AutoTArray<nsCString, 4> otherFamilyNames;
       gfxFontUtils::ReadOtherFamilyNamesForFace(familyName, data, size,
                                                 otherFamilyNames, false);
@@ -1491,13 +1491,13 @@ void gfxDWriteFontList::ReadFaceNamesForFamily(
               fullname, fontlist::LocalFaceRec::InitData(key, i));
         }
       }
-    }
-    MOZ_SEH_EXCEPT(EXCEPTION_EXECUTE_HANDLER) {
-      gfxCriticalNote << "Exception occurred reading names for "
-                      << familyName.get();
-    }
 
-    dwFontFace->ReleaseFontTable(context);
+      dwFontFace->ReleaseFontTable(context);
+    }
+  }
+  MOZ_SEH_EXCEPT(EXCEPTION_EXECUTE_HANDLER) {
+    gfxCriticalNote << "Exception occurred reading names for "
+                    << familyName.get();
   }
 }