Do not calculate composition bounds until IME requests.

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

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.content.browser.input;
 
 import android.content.res.Configuration;
 import android.os.Build;
 import android.os.ResultReceiver;
 import android.os.SystemClock;
@@ skipping 175 matching lines @@
             setInputConnection(null);
             if (DEBUG_LOGS) Log.w(TAG, "onCreateInputConnection returns null.");
             return null;
         }
         if (mInputConnectionFactory == null) return null;
         setInputConnection(mInputConnectionFactory.initializeAndGet(
                 mViewEmbedder.getAttachedView(), this, mTextInputType, mTextInputFlags,
                 mLastSelectionStart, mLastSelectionEnd, outAttrs));
         if (DEBUG_LOGS) Log.w(TAG, "onCreateInputConnection: " + mInputConnection);
         if (mCursorAnchorInfoController != null) {
-            mCursorAnchorInfoController.resetMonitoringState();
+            onRequestCursorUpdates(0 /* disable any cursor update */);

[yosin_UTC9, 2016/07/06 02:02:01]

How about
const int kDisableAnyCursorUpdate = 0;
onRequrestCursorUpdate(kDisplayAnyCursorUpdate);

[Seigo Nonaka, 2016/07/06 03:25:56]

Done.

         }
         return mInputConnection;
     }
 
     private void setInputConnection(ChromiumBaseInputConnection inputConnection) {
         if (mInputConnection == inputConnection) return;
         // The previous input connection might be waiting for state update.
         if (mInputConnection != null) mInputConnection.unblockOnUiThread();
         mInputConnection = inputConnection;
     }
@@ skipping 447 matching lines @@
         if (mNativeImeAdapterAndroid == 0) return false;
         // You won't get state update anyways.
         if (mInputConnection == null) return false;
         return nativeRequestTextInputStateUpdate(mNativeImeAdapterAndroid);
     }
 
     /**
      * Notified when IME requested Chrome to change the cursor update mode.
      */
     public boolean onRequestCursorUpdates(int cursorUpdateMode) {
+        if (mNativeImeAdapterAndroid != 0) {

[yosin_UTC9, 2016/07/06 02:02:01]

nit: Not need to have curly bracket.

[Seigo Nonaka, 2016/07/06 03:25:56]

Thanks, but presubmit warns if I removed curly braces.
Looks like we can drop curly braces only when it is single-line statement.

+            nativeRequestCursorUpdate(mNativeImeAdapterAndroid, cursorUpdateMode);
+        }
         if (mCursorAnchorInfoController == null) return false;
         return mCursorAnchorInfoController.onRequestCursorUpdates(cursorUpdateMode,
                 mViewEmbedder.getAttachedView());
     }
 
     /**
      * Notified when a frame has been produced by the renderer and all the associated metadata.
      * @param renderCoordinates coordinate information to convert CSS (document) coordinates to
      *                          View-local Physical (screen) coordinates
      * @param hasInsertionMarker Whether the insertion marker is visible or not.
@@ skipping 69 matching lines @@
     private native void nativeCommitText(long nativeImeAdapterAndroid, String textStr);
     private native void nativeFinishComposingText(long nativeImeAdapterAndroid);
     private native void nativeAttachImeAdapter(long nativeImeAdapterAndroid);
     private native void nativeSetEditableSelectionOffsets(long nativeImeAdapterAndroid,
             int start, int end);
     private native void nativeSetComposingRegion(long nativeImeAdapterAndroid, int start, int end);
     private native void nativeDeleteSurroundingText(long nativeImeAdapterAndroid,
             int before, int after);
     private native void nativeResetImeAdapter(long nativeImeAdapterAndroid);
     private native boolean nativeRequestTextInputStateUpdate(long nativeImeAdapterAndroid);
+    private native void nativeRequestCursorUpdate(long nativeImeAdapterAndroid, int mode);
     private native boolean nativeIsImeThreadEnabled(long nativeImeAdapterAndroid);
 }