[Android] Suppress unnecessary selection updates.

content/public/android/java/src/org/chromium/content/browser/ImeAdapter.java

Index: content/public/android/java/src/org/chromium/content/browser/ImeAdapter.java
diff --git a/content/public/android/java/src/org/chromium/content/browser/ImeAdapter.java b/content/public/android/java/src/org/chromium/content/browser/ImeAdapter.java
index 96f70be81ed207bbc996db25ddafe4f58ac82fe5..255013a9cbff5ff0d0a7b51b57ef300a020802e3 100644
--- a/content/public/android/java/src/org/chromium/content/browser/ImeAdapter.java
+++ b/content/public/android/java/src/org/chromium/content/browser/ImeAdapter.java
@@ -495,6 +495,7 @@ class ImeAdapter {
         private boolean mSingleLine;
         private int mNumNestedBatchEdits = 0;
         private boolean mIgnoreTextInputStateUpdates = false;
+        private boolean mPendingUpdate = false;
 
         private int mLastUpdateSelectionStart = INVALID_SELECTION;
         private int mLastUpdateSelectionEnd = INVALID_SELECTION;
@@ -548,15 +549,22 @@ class ImeAdapter {
                 return;
             }
 
-            Selection.setSelection(editable, selectionStart, selectionEnd);
+            if (prevSelectionStart != selectionStart || prevSelectionEnd != selectionEnd) {
+                Selection.setSelection(editable, selectionStart, selectionEnd);
+            }
 
-            if (compositionStart == compositionEnd) {
-                removeComposingSpans(getEditable());
-            } else {
-                super.setComposingRegion(compositionStart, compositionEnd);
+            if (prevCompositionStart != compositionStart || prevCompositionEnd != compositionEnd) {
+                if (compositionStart == compositionEnd) {
+                    removeComposingSpans(getEditable());
+                } else {
+                    super.setComposingRegion(compositionStart, compositionEnd);
+                }
             }
 
-            if (mIgnoreTextInputStateUpdates) return;
+            if (mIgnoreTextInputStateUpdates) {
+                mPendingUpdate = true;
+                return;
+            }
             updateSelection(selectionStart, selectionEnd, compositionStart, compositionEnd);
         }
 
@@ -564,6 +572,7 @@ class ImeAdapter {
         protected void updateSelection(
                 int selectionStart, int selectionEnd,
                 int compositionStart, int compositionEnd) {
+            mPendingUpdate = false;
             // Avoid sending update if we sent an exact update already previously.
             if (mLastUpdateSelectionStart == selectionStart &&

[aurimas (slooooooooow), 2013/04/10 14:35:46]

Can you explain why this if check for the last update would allow sending an
update though if we did not receive any setEditableText()? 

[Fredrik Öhrn, 2013/04/10 15:27:36]

When setIgnoreTextInputStateUpdates(false) calls this function the test will not
match if the on screen keyboard changed the selection or composition ranges
during the batch edit.

[aurimas (slooooooooow), 2013/04/10 15:49:12]

If the keyboard did change the selection or composition ranges, then why
wouldn't we want to send an update?

                     mLastUpdateSelectionEnd == selectionEnd &&
@@ -739,6 +748,7 @@ class ImeAdapter {
             if (DEBUG) Log.w(TAG, "restartInput");
             getInputMethodManagerWrapper().restartInput(mInternalView);
             mIgnoreTextInputStateUpdates = false;
+            mPendingUpdate = false;
             mNumNestedBatchEdits = 0;
         }
 
@@ -761,7 +771,7 @@ class ImeAdapter {
 
         void setIgnoreTextInputStateUpdates(boolean shouldIgnore) {
             mIgnoreTextInputStateUpdates = shouldIgnore;
-            if (shouldIgnore) return;
+            if (shouldIgnore || !mPendingUpdate) return;
 
             Editable editable = getEditable();
             updateSelection(Selection.getSelectionStart(editable),