Add more logging in ScreenCapturerIntegrationTest

ScreenCapturerIntegrationTest is flaky on Windows systems due to some unknown
reason. But it's do easily impacted by the environment, so this change adds more
logging (entire screenshot) to help debugging.
Meanwhile, this change also includes a nice-to-have change in ScreenDrawerWin to
always bring the window to front in each WaitForPendingDraws() function call. I
cannot quite tell whether this change can help to resolve the issue, but it is
worth trying.

BUG=webrtc:6666

Review-Url: https://codereview.webrtc.org/2492723002
Cr-Commit-Position: refs/heads/master@{#15158}

webrtc/modules/desktop_capture/screen_capturer_integration_test.cc

@@ -12,9 +12,12 @@
 
 #include <algorithm>
 #include <initializer_list>
+#include <iostream>  // TODO(zijiehe): Remove once flaky has been resolved.
 #include <memory>
 #include <utility>
 
+// TODO(zijiehe): Remove once flaky has been resolved.
+#include "webrtc/base/base64.h"
 #include "webrtc/base/checks.h"
 #include "webrtc/base/constructormagic.h"
 #include "webrtc/base/logging.h"
@@ -116,7 +119,9 @@ class ScreenCapturerIntegrationTest : public testing::Test {
         RgbaColor color((c == 0 ? (i & 0xff) : 0x7f),
                         (c == 1 ? (i & 0xff) : 0x7f),
                         (c == 2 ? (i & 0xff) : 0x7f));
-        TestCaptureOneFrame(capturers, drawer.get(), rect, color);
+        // Fail fast.
+        ASSERT_NO_FATAL_FAILURE(
+            TestCaptureOneFrame(capturers, drawer.get(), rect, color));
       }
 
       // A variable-size rectangle.
@@ -126,7 +131,9 @@ class ScreenCapturerIntegrationTest : public testing::Test {
         RgbaColor color((c == 0 ? (i & 0xff) : 0x7f),
                         (c == 1 ? (i & 0xff) : 0x7f),
                         (c == 2 ? (i & 0xff) : 0x7f));
-        TestCaptureOneFrame(capturers, drawer.get(), rect, color);
+        // Fail fast.
+        ASSERT_NO_FATAL_FAILURE(
+            TestCaptureOneFrame(capturers, drawer.get(), rect, color));
       }
     }
   }
@@ -183,14 +190,14 @@ class ScreenCapturerIntegrationTest : public testing::Test {
       for (size_t j = 0; j < capturers.size(); j++) {
         if (capturers[j] == nullptr) {
           // DesktopCapturer should return an empty updated_region() if no
-          // update detected. So we won't test it again if it has captured
-          // the rectangle we drew.
+          // update detected. So we won't test it again if it has captured the
+          // rectangle we drew.
           continue;
         }
         std::unique_ptr<DesktopFrame> frame = CaptureFrame(capturers[j]);
         if (!frame) {
-          // CaptureFrame() has triggered an assertion failure already, we
-          // only need to return here.
+          // CaptureFrame() has triggered an assertion failure already, we only
+          // need to return here.
           return;
         }
 
@@ -199,6 +206,35 @@ class ScreenCapturerIntegrationTest : public testing::Test {
           capturers[j] = nullptr;
           succeeded_capturers++;
         }
+        // The following else if statement is for debugging purpose only, which
+        // should be removed after flaky of ScreenCapturerIntegrationTest has
+        // been resolved.
+        else if (i == wait_capture_round - 1) {
+          std::string result;
+          rtc::Base64::EncodeFromArray(frame->data(),
+                                       frame->size().height() * frame->stride(),
+                                       &result);
+          std::cout << frame->size().width() << " x " << frame->size().height()
+                    << std::endl;
+          // Split the entire string (can be over 4M) into several lines to
+          // avoid browser from stucking.
+          static const size_t kLineLength = 32768;
+          const char* result_end = result.c_str() + result.length();
+          for (const char* it = result.c_str();
+               it < result_end;
+               it += kLineLength) {
+            const size_t max_length = result_end - it;
+            std::cout << std::string(it, std::min(kLineLength, max_length))
+                      << std::endl;
+          }
+          ASSERT_TRUE(false) << "ScreenCapturerIntegrationTest may be flaky. "
+                                "Please kindly FYI the broken link to "
+                                "zijiehe@chromium.org for investigation. If I "
+                                "have not responded as quick as expected, "
+                                "disable *all* tests in "
+                                "screen_capturer_integration_test.cc to "
+                                "unblock other developers.";
+        }
       }
 
       if (succeeded_capturers == capturers.size()) {

webrtc/modules/desktop_capture/screen_drawer_win.cc

@@ -150,6 +150,7 @@ void ScreenDrawerWin::Clear() {
 // TODO(zijiehe): Find the right signal to indicate the finish of all pending
 // paintings.
 void ScreenDrawerWin::WaitForPendingDraws() {
+  BringToFront();
   SleepMs(50);
 }