Disable learning text suggestions if in incognito.

chrome/android/java/src/org/chromium/chrome/browser/omnibox/UrlBar.java

Index: chrome/android/java/src/org/chromium/chrome/browser/omnibox/UrlBar.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/omnibox/UrlBar.java b/chrome/android/java/src/org/chromium/chrome/browser/omnibox/UrlBar.java
index f0c4e28f50f1ebc13f130246176aec3253084c3e..2f85cef41d82408897549e92f4a5c9fd55d6d904 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/omnibox/UrlBar.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/omnibox/UrlBar.java
@@ -27,6 +27,8 @@ import android.view.KeyEvent;
 import android.view.MotionEvent;
 import android.view.View;
 import android.view.accessibility.AccessibilityNodeInfo;
+import android.view.inputmethod.EditorInfo;
+import android.view.inputmethod.InputConnection;
 import android.widget.TextView;
 
 import org.chromium.base.ApiCompatibilityUtils;
@@ -55,6 +57,11 @@ public class UrlBar extends AutocompleteEditText {
 
     private static final boolean DEBUG = false;
 
+    // TODO(tedchoc): Replace with EditorInfoCompat#IME_FLAG_NO_PERSONALIZED_LEARNING or
+    //                EditorInfo#IME_FLAG_NO_PERSONALIZED_LEARNING as soon as either is available in
+    //                all build config types.
+    private static final int IME_FLAG_NO_PERSONALIZED_LEARNING = 0x1000000;
+
     // TextView becomes very slow on long strings, so we limit maximum length
     // of what is displayed to the user, see limitDisplayableLength().
     private static final int MAX_DISPLAYABLE_LENGTH = 4000;
@@ -141,6 +148,11 @@ public class UrlBar extends AutocompleteEditText {
         Tab getCurrentTab();
 
         /**
+         * @return Whether the user has entered incognito mode.
+         */
+        boolean isIncognito();
+
+        /**
          * Called when the text state has changed and the autocomplete suggestions should be
          * refreshed.
          *
@@ -640,6 +652,15 @@ public class UrlBar extends AutocompleteEditText {
     }
 
     @Override
+    public InputConnection onCreateInputConnection(EditorInfo outAttrs) {
+        InputConnection connection = super.onCreateInputConnection(outAttrs);
+        if (mUrlBarDelegate != null && mUrlBarDelegate.isIncognito()) {

[Changwan Ryu, 2017/05/23 18:54:23]

This should arguably be

assert mUrlBarDelegate != null;
if (mUrlBarDelegate.isIncognito()) {

to ensure the flag option without having to manually check all the call sites of
setDelegate(), but it's a bit scary because we need to depend on unspecified
android framework behavior..

Maybe we could have both assert and null check if we want to avoid crash while
keeping track of flag issue.. WDYT?

[Ted C, 2017/05/23 19:17:55]

I think the null and assert seems safest.  I would hope no android version
would call this as part of the constructor, but I have also no confidence
that some version doesn't do just that.

+            outAttrs.imeOptions |= IME_FLAG_NO_PERSONALIZED_LEARNING;
+        }
+        return connection;
+    }
+
+    @Override
     protected void onTextChanged(CharSequence text, int start, int lengthBefore, int lengthAfter) {
         super.onTextChanged(text, start, lengthBefore, lengthAfter);
         mIsPastedText = false;