Refactor autocomplete-specific logic into a separate class

Mostly just moving things around, but simplify call paths to
limitDisplayableLength().

Also, add a JUnit test to ensure that basic functions work.

BUG=722908

Review-Url: https://codereview.chromium.org/2885973002
Cr-Commit-Position: refs/heads/master@{#472681}
diff --git a/chrome/android/java_sources.gni b/chrome/android/java_sources.gni
index 4fbf2c5..1eac11d 100644
--- a/chrome/android/java_sources.gni
+++ b/chrome/android/java_sources.gni
@@ -705,6 +705,7 @@
   "java/src/org/chromium/chrome/browser/omnibox/AnswerTextBuilder.java",
   "java/src/org/chromium/chrome/browser/omnibox/AnswersImage.java",
   "java/src/org/chromium/chrome/browser/omnibox/AutocompleteController.java",
+  "java/src/org/chromium/chrome/browser/omnibox/AutocompleteEditText.java",
   "java/src/org/chromium/chrome/browser/omnibox/KeyboardHideHelper.java",
   "java/src/org/chromium/chrome/browser/omnibox/LocationBar.java",
   "java/src/org/chromium/chrome/browser/omnibox/LocationBarLayout.java",
@@ -1741,6 +1742,7 @@
   "junit/src/org/chromium/chrome/browser/offlinepages/prefetch/PrefetchBackgroundTaskTest.java",
   "junit/src/org/chromium/chrome/browser/omaha/ResponseParserTest.java",
   "junit/src/org/chromium/chrome/browser/omaha/VersionNumberTest.java",
+  "junit/src/org/chromium/chrome/browser/omnibox/AutocompleteEditTextTest.java",
   "junit/src/org/chromium/chrome/browser/omnibox/KeyboardHideHelperUnitTest.java",
   "junit/src/org/chromium/chrome/browser/omnibox/geo/VisibleNetworksTest.java",
   "junit/src/org/chromium/chrome/browser/omnibox/geo/PlatformNetworksManagerTest.java",