Mock DisplayMetrics in NotificationManagerTest

DisplayMetrics are used in some downstream branches and need to be
mocked. This avoids merge conflicts in NetworkNotificationManagerTest.

Partial cherry-pick of change IDs:
I35d28c8df341dbbac2774026c6ca749e296c0482
I1aeed1c79e4a829d8829eb08224f9b21fafc50fe

Test: atest NetworkNotificationManagerTest
Bug: 176239013
Merged-In: I3c2563d4ae4e3715d0c6270344ba8f7ef067872f
Change-Id: I118ec1af615aef36293bf0b480389f766122ccab

tests/unit/java/com/android/server/connectivity/NetworkNotificationManagerTest.java

@@ -51,6 +51,7 @@ import android.net.NetworkInfo;
 import android.os.Build;
 import android.os.UserHandle;
 import android.telephony.TelephonyManager;
+import android.util.DisplayMetrics;
 
 import androidx.test.filters.SmallTest;
 
@@ -103,6 +104,7 @@ public class NetworkNotificationManagerTest {
 
     @Mock Context mCtx;
     @Mock Resources mResources;
+    @Mock DisplayMetrics mDisplayMetrics;
     @Mock PackageManager mPm;
     @Mock TelephonyManager mTelephonyManager;
     @Mock NotificationManager mNotificationManager;
@@ -124,6 +126,7 @@ public class NetworkNotificationManagerTest {
         mCellNai.networkInfo = mNetworkInfo;
         mVpnNai.networkCapabilities = VPN_CAPABILITIES;
         mVpnNai.networkInfo = mNetworkInfo;
+        mDisplayMetrics.density = 2.275f;
         doReturn(true).when(mVpnNai).isVPN();
         when(mCtx.getResources()).thenReturn(mResources);
         when(mCtx.getPackageManager()).thenReturn(mPm);
@@ -136,6 +139,7 @@ public class NetworkNotificationManagerTest {
         when(mNetworkInfo.getExtraInfo()).thenReturn(TEST_EXTRA_INFO);
         ConnectivityResources.setResourcesContextForTest(mCtx);
         when(mResources.getColor(anyInt(), any())).thenReturn(0xFF607D8B);
+        when(mResources.getDisplayMetrics()).thenReturn(mDisplayMetrics);
 
         // Come up with some credible-looking transport names. The actual values do not matter.
         String[] transportNames = new String[NetworkCapabilities.MAX_TRANSPORT + 1];