Adds dryrun mode for Gold pixel diff

For local development, test owner don't need to actually upload anything.

Bug: 1145334
Change-Id: I2b7f2808d6bc10c7e6dbcfb99805ea52d2b3f152
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2522611Reviewed-by: Brian Sheedy <bsheedy@chromium.org>
Commit-Queue: Sven Zheng <svenzheng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#824720}

ui/base/test/skia_gold_pixel_diff.cc

@@ -12,6 +12,7 @@
 #include "third_party/skia/include/core/SkBitmap.h"
 
 #include "base/command_line.h"
+#include "base/environment.h"
 #include "base/files/file.h"
 #include "base/files/file_util.h"
 #include "base/json/json_reader.h"
@@ -55,6 +56,7 @@ const char* kCodeReviewSystemKey = "code-review-system";
 
 const char* kNoLuciAuth = "no-luci-auth";
 const char* kBypassSkiaGoldFunctionality = "bypass-skia-gold-functionality";
+const char* kDryRun = "dryrun";
 
 namespace {
 
@@ -145,6 +147,12 @@ bool FillInTestEnvironment(const base::FilePath& keys_file) {
   return true;
 }
 
+bool BotModeEnabled(const base::CommandLine* command_line) {
+  std::unique_ptr<base::Environment> env(base::Environment::Create());
+  return command_line->HasSwitch(switches::kTestLauncherBotMode) ||
+         env->HasVar("CHROMIUM_TEST_LAUNCHER_BOT_MODE");
+}
+
 }  // namespace
 
 SkiaGoldPixelDiff::SkiaGoldPixelDiff() = default;
@@ -245,8 +253,7 @@ void SkiaGoldPixelDiff::Init(const std::string& screenshot_prefix,
       code_review_system_ = "gerrit";
     }
   }
-  if (cmd_line->HasSwitch(kNoLuciAuth) ||
-      !cmd_line->HasSwitch(switches::kTestLauncherBotMode)) {
+  if (cmd_line->HasSwitch(kNoLuciAuth) || !BotModeEnabled(cmd_line)) {
     luci_auth_ = false;
   }
   initialized_ = true;
@@ -277,6 +284,10 @@ bool SkiaGoldPixelDiff::UploadToSkiaGoldServer(
   cmd.AppendSwitchPath("png-file", local_file_path);
   cmd.AppendSwitchPath("work-dir", working_dir_);
 
+  if (!BotModeEnabled(base::CommandLine::ForCurrentProcess())) {
+    cmd.AppendSwitch(kDryRun);
+  }
+
   std::map<std::string, std::string> optional_keys;
   if (!ShouldMakeGerritCommentsOnFailures()) {
     optional_keys["ignore"] = "1";

ui/base/test/skia_gold_pixel_diff_unittest.cc

@@ -346,5 +346,36 @@ TEST_F(SkiaGoldPixelDiffTest, MakeGerritCommentInvalidFlag) {
   EXPECT_TRUE(ret);
 }
 
+TEST_F(SkiaGoldPixelDiffTest, DryRunLocally) {
+  auto* cmd_line = base::CommandLine::ForCurrentProcess();
+  cmd_line->RemoveSwitch(switches::kTestLauncherBotMode);
+
+  MockSkiaGoldPixelDiff mock_pixel;
+  EXPECT_CALL(mock_pixel, LaunchProcess(_)).Times(AnyNumber());
+  EXPECT_CALL(
+      mock_pixel,
+      LaunchProcess(AllOf(Property(&base::CommandLine::GetCommandLineString,
+                                   HasSubstr(FILE_PATH_LITERAL("--dryrun"))))))
+      .Times(1);
+  mock_pixel.Init("Prefix");
+  bool ret = mock_pixel.CompareScreenshot("test", GetTestBitmap());
+  EXPECT_TRUE(ret);
+}
+
+TEST_F(SkiaGoldPixelDiffTest, NotDryRunOnBots) {
+  auto* cmd_line = base::CommandLine::ForCurrentProcess();
+  cmd_line->AppendSwitch(switches::kTestLauncherBotMode);
+
+  MockSkiaGoldPixelDiff mock_pixel;
+  EXPECT_CALL(mock_pixel, LaunchProcess(_)).Times(AnyNumber());
+  EXPECT_CALL(mock_pixel, LaunchProcess(AllOf(Property(
+                              &base::CommandLine::GetCommandLineString,
+                              Not(HasSubstr(FILE_PATH_LITERAL("--dryrun")))))))
+      .Times(3);
+  mock_pixel.Init("Prefix");
+  bool ret = mock_pixel.CompareScreenshot("test", GetTestBitmap());
+  EXPECT_TRUE(ret);
+}
+
 }  // namespace test
 }  // namespace ui