Address NewApi Android lint warnings in src/content.

Annotate several classes with @TargetApi so lint knows that those
classes can safely use methods introduced in various versions of
Android.

BUG=266140

Review URL: https://codereview.chromium.org/963383002

Cr-Commit-Position: refs/heads/master@{#318751}

content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java

@@ -5,6 +5,7 @@
 package org.chromium.content.browser;
 
 import android.annotation.SuppressLint;
+import android.annotation.TargetApi;
 import android.app.Activity;
 import android.app.SearchManager;
 import android.content.ClipboardManager;
@@ -2806,6 +2807,7 @@ public class ContentViewCore
     /**
      * @see View#onInitializeAccessibilityEvent(AccessibilityEvent)
      */
+    @TargetApi(Build.VERSION_CODES.ICE_CREAM_SANDWICH_MR1)
     public void onInitializeAccessibilityEvent(AccessibilityEvent event) {
         // Note: this is only used by the script-injecting accessibility code.
         event.setClassName(this.getClass().getName());
@@ -2820,9 +2822,7 @@ public class ContentViewCore
         int maxScrollYPix = Math.max(0, mRenderCoordinates.getMaxVerticalScrollPixInt());
         event.setScrollable(maxScrollXPix > 0 || maxScrollYPix > 0);
 
-        // Setting the maximum scroll values requires API level 15 or higher.
-        final int sdkVersionRequiredToSetScroll = 15;
-        if (Build.VERSION.SDK_INT >= sdkVersionRequiredToSetScroll) {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH_MR1) {
             event.setMaxScrollX(maxScrollXPix);
             event.setMaxScrollY(maxScrollYPix);
         }

content/public/android/java/src/org/chromium/content/browser/accessibility/BrowserAccessibilityManager.java

@@ -4,6 +4,7 @@
 
 package org.chromium.content.browser.accessibility;
 
+import android.annotation.TargetApi;
 import android.content.Context;
 import android.graphics.Rect;
 import android.os.Build;
@@ -38,6 +39,7 @@ import java.util.Locale;
  * accessibility.
  */
 @JNINamespace("content")
+@TargetApi(Build.VERSION_CODES.JELLY_BEAN)
 public class BrowserAccessibilityManager {
     private static final String TAG = "BrowserAccessibilityManager";
 

content/public/android/java/src/org/chromium/content/browser/accessibility/JellyBeanAccessibilityInjector.java

@@ -4,7 +4,9 @@
 
 package org.chromium.content.browser.accessibility;
 
+import android.annotation.TargetApi;
 import android.content.Context;
+import android.os.Build;
 import android.os.Bundle;
 import android.os.SystemClock;
 import android.view.accessibility.AccessibilityNodeInfo;
@@ -22,6 +24,7 @@ import java.util.concurrent.atomic.AtomicInteger;
  * Handles injecting accessibility Javascript and related Javascript -> Java APIs for JB and newer
  * devices.
  */
+@TargetApi(Build.VERSION_CODES.JELLY_BEAN)
 class JellyBeanAccessibilityInjector extends AccessibilityInjector {
     private CallbackHandler mCallback;
     private JSONObject mAccessibilityJSONObject;

content/public/android/java/src/org/chromium/content/browser/accessibility/JellyBeanBrowserAccessibilityManager.java

@@ -4,6 +4,8 @@
 
 package org.chromium.content.browser.accessibility;
 
+import android.annotation.TargetApi;
+import android.os.Build;
 import android.os.Bundle;
 import android.view.accessibility.AccessibilityNodeInfo;
 import android.view.accessibility.AccessibilityNodeProvider;
@@ -18,6 +20,7 @@ import java.util.List;
  * AccessibilityNodeProvider and delegates its implementation to this object.
  */
 @JNINamespace("content")
+@TargetApi(Build.VERSION_CODES.JELLY_BEAN)
 public class JellyBeanBrowserAccessibilityManager extends BrowserAccessibilityManager {
     private AccessibilityNodeProvider mAccessibilityNodeProvider;
 

content/public/android/java/src/org/chromium/content/browser/accessibility/LollipopAccessibilityInjector.java

@@ -4,7 +4,9 @@
 
 package org.chromium.content.browser.accessibility;
 
+import android.annotation.TargetApi;
 import android.content.Context;
+import android.os.Build;
 import android.os.Bundle;
 import android.view.View;
 import android.view.accessibility.AccessibilityNodeInfo;
@@ -20,6 +22,7 @@ import java.util.Iterator;
  * Handles injecting accessibility Javascript and related Javascript -> Java APIs for Lollipop and
  * newer devices.
  */
+@TargetApi(Build.VERSION_CODES.LOLLIPOP)
 class LollipopAccessibilityInjector extends JellyBeanAccessibilityInjector {
     /**
      * Constructs an instance of the LollipopAccessibilityInjector.

content/public/android/java/src/org/chromium/content/browser/accessibility/LollipopBrowserAccessibilityManager.java

@@ -4,6 +4,8 @@
 
 package org.chromium.content.browser.accessibility;
 
+import android.annotation.TargetApi;
+import android.os.Build;
 import android.view.accessibility.AccessibilityEvent;
 import android.view.accessibility.AccessibilityNodeInfo;
 import android.view.accessibility.AccessibilityNodeInfo.AccessibilityAction;
@@ -17,6 +19,7 @@ import org.chromium.content.browser.ContentViewCore;
  * AccessibilityNodeProvider and delegates its implementation to this object.
  */
 @JNINamespace("content")
+@TargetApi(Build.VERSION_CODES.LOLLIPOP)
 public class LollipopBrowserAccessibilityManager extends JellyBeanBrowserAccessibilityManager {
     LollipopBrowserAccessibilityManager(long nativeBrowserAccessibilityManagerAndroid,
             ContentViewCore contentViewCore) {