Add startImeTrace and stopImeTrace APIs in ImeTracing

So Settings DevelopmentTiles doesn't need to create direct
IInputMethodManager dependency to access system API.

Bug: 175742251
Test: Manually test ime winscope works properly
Test: make RunSettingsRoboTests ROBOTEST_FILTER="WinscopeTraceTest"
Change-Id: Ie37790c7479f6b9064afd7fbcee7fd6f712d1a75

core/java/com/android/internal/inputmethod/ImeTracing.java

@@ -91,6 +91,28 @@ public abstract class ImeTracing {
         mService.startProtoDump(protoDump, source, where);
     }
 
+    /**
+     * Calling {@link IInputMethodManager#startImeTrace()}} to capture IME trace.
+     */
+    public final void startImeTrace() {
+        try {
+            mService.startImeTrace();
+        } catch (RemoteException e) {
+            Log.e(TAG, "Could not start ime trace." + e);
+        }
+    }
+
+    /**
+     * Calling {@link IInputMethodManager#stopImeTrace()} to stop IME trace.
+     */
+    public final void stopImeTrace() {
+        try {
+            mService.stopImeTrace();
+        } catch (RemoteException e) {
+            Log.e(TAG, "Could not stop ime trace." + e);
+        }
+    }
+
     /**
      * @param proto dump to be added to the buffer
      */