[context menu] add print page test for empty space CM

chrome/android/javatests/src/org/chromium/chrome/browser/contextmenu/ContextMenuTest.java \
      --gtest_filter=ContextMenuTest.testPrintPage

Bug: 391719844
Test: tools/autotest.py -C out/android_x64/ \
Change-Id: If88bd2f4278be0b6117a373c6a431724686e0ca2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6482169
Reviewed-by: Lei Zhang <thestig@chromium.org>
Reviewed-by: Sinan Sahin <sinansahin@google.com>
Commit-Queue: Lei Zhang <thestig@chromium.org>
Auto-Submit: Grace Cham <hscham@chromium.org>
Reviewed-by: Benjamin Gordon <bmgordon@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1454276}

chrome/android/javatests/src/org/chromium/chrome/browser/contextmenu/ContextMenuTest.java

@@ -95,6 +95,9 @@ import org.chromium.content_public.browser.test.util.DOMUtils;
 import org.chromium.content_public.browser.test.util.TestTouchUtils;
 import org.chromium.content_public.common.ContentFeatures;
 import org.chromium.net.test.EmbeddedTestServer;
+import org.chromium.printing.Printable;
+import org.chromium.printing.PrintingController;
+import org.chromium.printing.PrintingControllerImpl;
 import org.chromium.ui.base.Clipboard;
 import org.chromium.ui.base.DeviceFormFactor;
 import org.chromium.ui.mojom.MenuSourceType;
@@ -118,6 +121,7 @@ public class ContextMenuTest {
 
     @Mock private TabContextMenuItemDelegate mItemDelegate;
     @Mock private ShareDelegate mShareDelegate;
+    @Mock private PrintingController mPrintingController;
     @Mock private DataProtectionBridge.Natives mDataProtectionBridgeMock;
 
     @ClassRule
@@ -1192,6 +1196,31 @@ public class ContextMenuTest {
                 chromeExtrasCaptor.getValue().saveLastUsed());
     }
 
+    @Test
+    @MediumTest
+    @Restriction(DeviceFormFactor.DESKTOP)
+    @EnableFeatures({ChromeFeatureList.CONTEXT_MENU_EMPTY_SPACE})
+    public void testPrintPage() throws Exception {
+        Tab tab = sDownloadTestRule.getActivity().getActivityTab();
+        ThreadUtils.runOnUiThreadBlocking(
+                // Set printing controller to use the mock instance.
+                () -> {
+                    PrintingControllerImpl.setInstanceForTesting(mPrintingController);
+                });
+
+        ContextMenuUtils.selectContextMenuItemFromRightClick(
+                InstrumentationRegistry.getInstrumentation(),
+                sDownloadTestRule.getActivity(),
+                tab,
+                "testEmptySpace",
+                R.id.contextmenu_print_page);
+
+        // Check that the started print job has the same title as the current tab.
+        ArgumentCaptor<Printable> printableCaptor = ArgumentCaptor.forClass(Printable.class);
+        verify(mPrintingController).startPrint(printableCaptor.capture(), any());
+        Assert.assertEquals(tab.getTitle(), printableCaptor.getValue().getTitle());
+    }
+
     // TODO(benwgold): Add more test coverage for histogram recording of other context menu types.
 
     /**

printing/android/java/src/org/chromium/printing/PrintingControllerImpl.java

@@ -16,6 +16,7 @@ import android.print.PrintDocumentInfo;
 import androidx.annotation.VisibleForTesting;
 
 import org.chromium.base.Log;
+import org.chromium.base.ResettersForTesting;
 import org.chromium.base.ThreadUtils;
 import org.chromium.build.annotations.NullMarked;
 import org.chromium.build.annotations.Nullable;
@@ -58,6 +59,8 @@ public class PrintingControllerImpl implements PrintingController, PdfGenerator
     /** The singleton instance for this class. */
     @VisibleForTesting protected static @Nullable PrintingController sInstance;
 
+    private static @Nullable PrintingController sInstanceForTesting;
+
     private @Nullable String mErrorMessage;
 
     private int mRenderProcessId;
@@ -103,6 +106,11 @@ public class PrintingControllerImpl implements PrintingController, PdfGenerator
         mPrintDocumentAdapterWrapper = new PrintDocumentAdapterWrapper(this);
     }
 
+    public static void setInstanceForTesting(PrintingController instanceForTesting) {
+        sInstanceForTesting = instanceForTesting;
+        ResettersForTesting.register(() -> sInstanceForTesting = null);
+    }
+
     /**
      * Returns the singleton instance, lazily creating one if needed.
      *
@@ -111,6 +119,8 @@ public class PrintingControllerImpl implements PrintingController, PdfGenerator
     public static PrintingController getInstance() {
         ThreadUtils.assertOnUiThread();
 
+        if (sInstanceForTesting != null) return sInstanceForTesting;
+
         if (sInstance == null) {
             sInstance = new PrintingControllerImpl();
         }
@@ -152,6 +162,11 @@ public class PrintingControllerImpl implements PrintingController, PdfGenerator
         return mIsBusy;
     }
 
+    @VisibleForTesting
+    public @Nullable Printable getPrintable() {
+        return mPrintable;
+    }
+
     @Override
     public void setPendingPrint(
             final Printable printable,