Bug 1310833: Modify PContentParent::SendActivateA11y to accept the content process's MSAA ID as a parameter; r=tbsaunde

MozReview-Commit-ID: 9OIpO0G0Q7j

accessible/windows/msaa/MsaaIdGenerator.cpp

@@ -85,16 +85,14 @@ private:
 
 constexpr MsaaIdGenerator::MsaaIdGenerator()
   : mIDSet(kNumUniqueIDBits)
-  , mContentProcessID(0)
 {}
 
 uint32_t
 MsaaIdGenerator::GetID()
 {
-  static const uint32_t kContentProcessId = ResolveContentProcessID();
   uint32_t id = mIDSet.GetID();
   MOZ_ASSERT(id <= ((1UL << kNumUniqueIDBits) - 1UL));
-  return detail::BuildMsaaID(id, kContentProcessId);
+  return detail::BuildMsaaID(id, ResolveContentProcessID());
 }
 
 void
@@ -104,7 +102,7 @@ MsaaIdGenerator::ReleaseID(AccessibleWrap* aAccWrap)
   uint32_t id = aAccWrap->GetExistingID();
   MOZ_ASSERT(id != AccessibleWrap::kNoID);
   detail::MsaaIDCracker cracked(id);
-  if (cracked.GetContentProcessId() != mContentProcessID) {
+  if (cracked.GetContentProcessId() != ResolveContentProcessID()) {
     // This may happen if chrome holds a proxy whose ID was originally generated
     // by a content process. Since ReleaseID only has meaning in the process
     // that originally generated that ID, we ignore ReleaseID calls for any ID
@@ -126,9 +124,8 @@ bool
 MsaaIdGenerator::IsIDForThisContentProcess(uint32_t aID)
 {
   MOZ_ASSERT(XRE_IsContentProcess());
-  static const uint32_t kContentProcessId = ResolveContentProcessID();
   detail::MsaaIDCracker cracked(aID);
-  return cracked.GetContentProcessId() == kContentProcessId;
+  return cracked.GetContentProcessId() == ResolveContentProcessID();
 }
 
 bool
@@ -158,10 +155,10 @@ MsaaIdGenerator::ResolveContentProcessID()
   }
 
   dom::ContentChild* contentChild = dom::ContentChild::GetSingleton();
-  Unused << contentChild->SendGetA11yContentId(&mContentProcessID);
+  uint32_t result = contentChild->GetMsaaID();
 
-  MOZ_ASSERT(mContentProcessID);
-  return mContentProcessID;
+  MOZ_ASSERT(result);
+  return result;
 }
 
 /**

accessible/windows/msaa/MsaaIdGenerator.h

@@ -48,7 +48,6 @@ private:
 
 private:
   IDSet     mIDSet;
-  uint32_t  mContentProcessID;
 };
 
 } // namespace a11y

dom/ipc/ContentChild.cpp

@@ -507,6 +507,9 @@ ContentChild* ContentChild::sSingleton;
 
 ContentChild::ContentChild()
  : mID(uint64_t(-1))
+#if defined(XP_WIN) && defined(ACCESSIBILITY)
+ , mMsaaID(0)
+#endif
  , mCanOverrideProcessName(true)
  , mIsAlive(true)
  , mShuttingDown(false)
@@ -2445,13 +2448,18 @@ ContentChild::RecvFlushMemory(const nsString& reason)
 }
 
 bool
-ContentChild::RecvActivateA11y()
+ContentChild::RecvActivateA11y(const uint32_t& aMsaaID)
 {
 #ifdef ACCESSIBILITY
+#ifdef XP_WIN
+  MOZ_ASSERT(aMsaaID != 0);
+  mMsaaID = aMsaaID;
+#endif // XP_WIN
+
   // Start accessibility in content process if it's running in chrome
   // process.
   GetOrCreateAccService(nsAccessibilityService::eMainProcess);
-#endif
+#endif // ACCESSIBILITY
   return true;
 }
 

dom/ipc/ContentChild.h

@@ -446,7 +446,7 @@ public:
 
   virtual bool RecvFlushMemory(const nsString& reason) override;
 
-  virtual bool RecvActivateA11y() override;
+  virtual bool RecvActivateA11y(const uint32_t& aMsaaID) override;
   virtual bool RecvShutdownA11y() override;
 
   virtual bool RecvGarbageCollect() override;
@@ -567,6 +567,10 @@ public:
 
   ContentParentId GetID() const { return mID; }
 
+#if defined(XP_WIN) && defined(ACCESSIBILITY)
+  uint32_t GetMsaaID() const { return mMsaaID; }
+#endif
+
   bool IsForApp() const { return mIsForApp; }
   bool IsForBrowser() const { return mIsForBrowser; }
 
@@ -687,6 +691,14 @@ private:
    */
   ContentParentId mID;
 
+#if defined(XP_WIN) && defined(ACCESSIBILITY)
+  /**
+   * This is an a11y-specific unique id for the content process that is
+   * generated by the chrome process.
+   */
+  uint32_t mMsaaID;
+#endif
+
   AppInfo mAppInfo;
 
   bool mIsForApp;

dom/ipc/ContentParent.cpp

@@ -1361,10 +1361,11 @@ ContentParent::Init()
   if (nsIPresShell::IsAccessibilityActive()) {
 #if defined(XP_WIN)
     if (IsVistaOrLater()) {
-      Unused << SendActivateA11y();
+      Unused <<
+        SendActivateA11y(a11y::AccessibleWrap::GetContentProcessIdFor(ChildID()));
     }
 #else
-    Unused << SendActivateA11y();
+    Unused << SendActivateA11y(0);
 #endif
   }
 #endif
@@ -2790,10 +2791,11 @@ ContentParent::Observe(nsISupports* aSubject,
       // accessibility gets initiated in chrome process.
 #if defined(XP_WIN)
       if (IsVistaOrLater()) {
-        Unused << SendActivateA11y();
+        Unused <<
+          SendActivateA11y(a11y::AccessibleWrap::GetContentProcessIdFor(ChildID()));
       }
 #else
-      Unused << SendActivateA11y();
+      Unused << SendActivateA11y(0);
 #endif
     } else {
       // If possible, shut down accessibility in content process when
@@ -5198,18 +5200,6 @@ ContentParent::RecvUnstoreAndBroadcastBlobURLUnregistration(const nsCString& aUR
   return true;
 }
 
-bool
-ContentParent::RecvGetA11yContentId(uint32_t* aContentId)
-{
-#if defined(XP_WIN32) && defined(ACCESSIBILITY)
-  *aContentId = a11y::AccessibleWrap::GetContentProcessIdFor(ChildID());
-  MOZ_ASSERT(*aContentId);
-  return true;
-#else
-  return false;
-#endif
-}
-
 } // namespace dom
 } // namespace mozilla
 

dom/ipc/ContentParent.h

@@ -553,9 +553,6 @@ public:
   virtual bool
   RecvUnstoreAndBroadcastBlobURLUnregistration(const nsCString& aURI) override;
 
-  virtual bool
-  RecvGetA11yContentId(uint32_t* aContentId) override;
-
   virtual int32_t Pid() const override;
 
   // Use the PHangMonitor channel to ask the child to repaint a tab.

dom/ipc/PContent.ipdl

@@ -511,8 +511,11 @@ child:
 
     /**
      * Start accessibility engine in content process.
+     * @param aMsaaID is an a11y-specific unique id for the content process
+     *                that is generated by the chrome process. Only used on
+     *                Windows; pass 0 on other platforms.
      */
-    async ActivateA11y();
+    async ActivateA11y(uint32_t aMsaaID);
 
     /**
      * Shutdown accessibility engine in content process (if not in use).
@@ -1185,8 +1188,6 @@ parent:
     async AccumulateChildHistogram(Accumulation[] accumulations);
     async AccumulateChildKeyedHistogram(KeyedAccumulation[] accumulations);
 
-     sync GetA11yContentId() returns (uint32_t aContentId);
-
 both:
      async AsyncMessage(nsString aMessage, CpowEntry[] aCpows,
                         Principal aPrincipal, ClonedMessageData aData);