Revert "Hooking memory pressure signal to freeMemory in debug builds."

This reverts commit 767c3f7e0a6bffb9f3e17ec565610b178c4a3f95.

Change-Id: I09454cdc4d72baff1b200c8832ea9268e138bd0a
diff --git a/chromium/java/com/android/webview/chromium/WebViewChromium.java b/chromium/java/com/android/webview/chromium/WebViewChromium.java
index f1343c0..12c1567 100644
--- a/chromium/java/com/android/webview/chromium/WebViewChromium.java
+++ b/chromium/java/com/android/webview/chromium/WebViewChromium.java
@@ -16,7 +16,6 @@
 
 package com.android.webview.chromium;
 
-import android.content.ComponentCallbacks2;
 import android.content.res.Configuration;
 import android.graphics.Bitmap;
 import android.graphics.Canvas;
@@ -55,7 +54,6 @@
 
 import org.chromium.android_webview.AwBrowserContext;
 import org.chromium.android_webview.AwContents;
-import org.chromium.base.MemoryPressureListener;
 import org.chromium.base.ThreadUtils;
 import org.chromium.content.browser.LoadUrlParams;
 import org.chromium.net.NetworkChangeNotifier;
@@ -590,14 +588,7 @@
     @Override
     public void freeMemory() {
         checkThread();
-        // This method is not intended to have any effect on release builds,
-        // since memory is managed automatically by Chromium.
-        // However, in debug builds, this method is exploited by our WebView
-        // memory benchmarks to synthesize the memory pressure signal.
-        if (Build.IS_DEBUGGABLE) {
-            MemoryPressureListener.simulateMemoryPressureSignal(
-                    ComponentCallbacks2.TRIM_MEMORY_COMPLETE);
-        }
+        // Intentional no-op. Memory is managed automatically by Chromium.
     }
 
     @Override