Add xcode version for Mac OS 10.15.4 in osx_sdk

Adding a version map entry for 10.15.6 to default to XCode 12
GM (12a7209) as machines upgrade to 10.15.

Bug: 1128042, 1128044
Change-Id: I6396b67fdce006d19be35d972602bac3bd4ae0a7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2422449
Reviewed-by: Dirk Pranke <dpranke@google.com>
Commit-Queue: Jeff Yoon <jeffyoon@chromium.org>
diff --git a/recipes/README.recipes.md b/recipes/README.recipes.md
index 2dcd39d..3f1ce08 100644
--- a/recipes/README.recipes.md
+++ b/recipes/README.recipes.md
@@ -688,11 +688,11 @@
 
 Available only to Google-run bots.
 
-#### **class [OSXSDKApi](/recipes/recipe_modules/osx_sdk/api.py#35)([RecipeApi][recipe_engine/wkt/RecipeApi]):**
+#### **class [OSXSDKApi](/recipes/recipe_modules/osx_sdk/api.py#36)([RecipeApi][recipe_engine/wkt/RecipeApi]):**
 
 API for using OS X SDK distributed via CIPD.
 
-&emsp; **@contextmanager**<br>&mdash; **def [\_\_call\_\_](/recipes/recipe_modules/osx_sdk/api.py#61)(self, kind):**
+&emsp; **@contextmanager**<br>&mdash; **def [\_\_call\_\_](/recipes/recipe_modules/osx_sdk/api.py#62)(self, kind):**
 
 Sets up the XCode SDK environment.
 
@@ -740,7 +740,7 @@
 Raises:
     StepFailure or InfraFailure.
 
-&mdash; **def [initialize](/recipes/recipe_modules/osx_sdk/api.py#46)(self):**
+&mdash; **def [initialize](/recipes/recipe_modules/osx_sdk/api.py#47)(self):**
 ### *recipe_modules* / [presubmit](/recipes/recipe_modules/presubmit)
 
 [DEPS](/recipes/recipe_modules/presubmit/__init__.py#11): [bot\_update](#recipe_modules-bot_update), [depot\_tools](#recipe_modules-depot_tools), [gclient](#recipe_modules-gclient), [git](#recipe_modules-git), [tryserver](#recipe_modules-tryserver), [recipe\_engine/context][recipe_engine/recipe_modules/context], [recipe\_engine/cq][recipe_engine/recipe_modules/cq], [recipe\_engine/json][recipe_engine/recipe_modules/json], [recipe\_engine/path][recipe_engine/recipe_modules/path], [recipe\_engine/properties][recipe_engine/recipe_modules/properties], [recipe\_engine/python][recipe_engine/recipe_modules/python], [recipe\_engine/resultdb][recipe_engine/recipe_modules/resultdb], [recipe\_engine/step][recipe_engine/recipe_modules/step]
diff --git a/recipes/recipe_modules/osx_sdk/api.py b/recipes/recipe_modules/osx_sdk/api.py
index 92f650b..f1fa0e7 100644
--- a/recipes/recipe_modules/osx_sdk/api.py
+++ b/recipes/recipe_modules/osx_sdk/api.py
@@ -29,6 +29,7 @@
   ('10.13.6', '10b61'),
   ('10.14.3', '10g8'),
   ('10.14.4', '11b52'),
+  ('10.15.4', '12a7209')
 ]
 
 
diff --git a/recipes/recipe_modules/osx_sdk/examples/full.expected/automatic_version.json b/recipes/recipe_modules/osx_sdk/examples/full.expected/automatic_version.json
index fc809e9..002ae21 100644
--- a/recipes/recipe_modules/osx_sdk/examples/full.expected/automatic_version.json
+++ b/recipes/recipe_modules/osx_sdk/examples/full.expected/automatic_version.json
@@ -35,7 +35,7 @@
       "-kind",
       "mac",
       "-xcode-version",
-      "11b52",
+      "12a7209",
       "-output-dir",
       "[CACHE]/osx_sdk/XCode.app"
     ],
diff --git a/recipes/recipe_modules/osx_sdk/examples/full.py b/recipes/recipe_modules/osx_sdk/examples/full.py
index bdb7066..abb7f88 100644
--- a/recipes/recipe_modules/osx_sdk/examples/full.py
+++ b/recipes/recipe_modules/osx_sdk/examples/full.py
@@ -32,7 +32,7 @@
   yield api.test(
       'automatic_version',
       api.platform.name('mac'),
-      api.platform.mac_release('10.14.5'),
+      api.platform.mac_release('10.15.6'),
   )
 
   yield api.test(