Issue #1348 - Part 3: Set IS_PRIVATE input scope in private browsing.

Microsoft IME on Windows 10 20H1 (build 19025+) supports IME private
mode by input scope. Although previous Windows versions use an
undocumented API for Edge and IE only, the next Windows 10 release will
use a public API for it.
We pre-empt this potential privacy concern by setting the IS_PRIVATE
flag when in PB mode.

1 files changed, 12 insertions, 3 deletions

diff --git a/widget/windows/TSFTextStore.cpp b/widget/windows/TSFTextStore.cpp
index c80de831c9..12b8cd0c11 100644
--- a/widget/windows/TSFTextStore.cpp
+++ b/widget/windows/TSFTextStore.cpp
@@ -1355,7 +1355,9 @@ TSFTextStore::Init(nsWindowBase* aWidget,
     return false;
   }
 
-  SetInputScope(aContext.mHTMLInputType, aContext.mHTMLInputInputmode);
+  SetInputScope(aContext.mHTMLInputType,
+                aContext.mHTMLInputInputmode,
+                aContext.mInPrivateBrowsing);
 
   // Create document manager
   RefPtr<ITfThreadMgr> threadMgr = sThreadMgr;
@@ -3205,9 +3207,15 @@ TSFTextStore::InsertEmbedded(DWORD dwFlags,
 
 void
 TSFTextStore::SetInputScope(const nsString& aHTMLInputType,
-                            const nsString& aHTMLInputInputMode)
+                            const nsString& aHTMLInputInputMode,
+                            bool aInPrivateBrowsing)
 {
   mInputScopes.Clear();
+  
+  if (aInPrivateBrowsing) {
+    mInputScopes.AppendElement(IS_PRIVATE);
+  }
+  
   if (aHTMLInputType.IsEmpty() || aHTMLInputType.EqualsLiteral("text")) {
     if (aHTMLInputInputMode.EqualsLiteral("url")) {
       mInputScopes.AppendElement(IS_URL);
@@ -5688,7 +5696,8 @@ TSFTextStore::SetInputContext(nsWindowBase* aWidget,
     if (sEnabledTextStore) {
       RefPtr<TSFTextStore> textStore(sEnabledTextStore);
       textStore->SetInputScope(aContext.mHTMLInputType,
-                               aContext.mHTMLInputInputmode);
+                               aContext.mHTMLInputInputmode,
+                               aContext.mInPrivateBrowsing);
     }
     return;
   }