[build] Remove unused checkout_root arg

Change-Id: Ie5c589471b12b2c7a02524137d70fe7a535c7c91
diff --git a/recipe_modules/build/api.py b/recipe_modules/build/api.py
index 8f18bc5..7bf4edf 100644
--- a/recipe_modules/build/api.py
+++ b/recipe_modules/build/api.py
@@ -957,7 +957,6 @@
       return self.GNResults(self.m, fuchsia_build_dir, export_compdb)
 
   def ninja(self,
-            checkout_root,
             gn_results,
             targets=(),
             zircon_targets=(),
@@ -975,7 +974,6 @@
     through GNResults - in determining what to run.
 
     Args:
-      checkout_root (str): The fuchsia checkout root.
       gn_results (GNResults): GN gen results.
       targets (seq(str)): Fuchsia ninja targets.
       zircon_targets (seq(str)): Zircon ninja targets.
@@ -1120,7 +1118,6 @@
                                    'breakpad_symbols.tar.gz'))
 
       self.ninja(
-          checkout_root=checkout_root,
           gn_results=gn_results,
           gcs_bucket=gcs_bucket,
           targets=ninja_targets,
diff --git a/recipe_modules/build/examples/full.py b/recipe_modules/build/examples/full.py
index e535cf0..acfc88a 100644
--- a/recipe_modules/build/examples/full.py
+++ b/recipe_modules/build/examples/full.py
@@ -180,7 +180,6 @@
   gn_results.zbi_tests  # pylint: disable=pointless-statement
 
   api.build.ninja(
-      checkout_root=api.path['start_dir'],
       gn_results=gn_results,
       build_generated_sources=True,
       build_zbi_tests=True,
diff --git a/recipe_modules/debug_symbols/api.py b/recipe_modules/debug_symbols/api.py
index 03ad172..bff43826 100644
--- a/recipe_modules/debug_symbols/api.py
+++ b/recipe_modules/debug_symbols/api.py
@@ -56,7 +56,6 @@
           str(gn_results.fuchsia_build_dir),
       )
       self.m.build.ninja(
-          checkout_root=checkout_root,
           gn_results=gn_results,
           build_zircon=False,
           targets=[upload_debug_symbols_target],
diff --git a/recipe_modules/tricium_analyze/api.py b/recipe_modules/tricium_analyze/api.py
index 74d55ac..5a31811 100644
--- a/recipe_modules/tricium_analyze/api.py
+++ b/recipe_modules/tricium_analyze/api.py
@@ -120,7 +120,6 @@
       if 'FidlLint' not in self._analyses_run and 'FidlFormat' not in self._analyses_run:
         # Build the tool.
         self.m.build.ninja(
-            checkout_root=self.checkout.root_dir,
             gn_results=self._gn_results,
             zircon_targets=['tools'],
             build_canonical_zircon_targets=False,
@@ -219,7 +218,6 @@
       if 'FidlLint' not in self._analyses_run and 'FidlFormat' not in self._analyses_run:
         # Build the tool.
         self.m.build.ninja(
-            checkout_root=self.checkout.root_dir,
             gn_results=self._gn_results,
             zircon_targets=['tools'],
             build_canonical_zircon_targets=False,
@@ -319,7 +317,6 @@
 
     with self.m.step.nest('clang-tidy'):
       self.m.build.ninja(
-          checkout_root=self.checkout.root_dir,
           gn_results=self._gn_results,
           zircon_targets=['tools'],
           build_canonical_zircon_targets=False,
diff --git a/recipes/dart_flutter_roller.py b/recipes/dart_flutter_roller.py
index f28f7d0..ba20427 100644
--- a/recipes/dart_flutter_roller.py
+++ b/recipes/dart_flutter_roller.py
@@ -409,7 +409,6 @@
         str(gn_results.fuchsia_build_dir),
     )
     api.build.ninja(
-        checkout_root=api.path['start_dir'],
         gn_results=gn_results,
         build_zircon=False,
         targets=[upload_debug_symbols_target],
diff --git a/recipes/doc_checker.py b/recipes/doc_checker.py
index 2daf450..e8db99e 100644
--- a/recipes/doc_checker.py
+++ b/recipes/doc_checker.py
@@ -51,7 +51,6 @@
     )
 
     api.build.ninja(
-        checkout_root=checkout_root_dir,
         gn_results=gn_results,
         targets=[doc_checker_output_path],
         # Skip building zircon since it is unnecessary
diff --git a/recipes/firebase_docs.py b/recipes/firebase_docs.py
index 2a393a1c..2ebeefc 100644
--- a/recipes/firebase_docs.py
+++ b/recipes/firebase_docs.py
@@ -356,10 +356,7 @@
       export_compdb=True,
   )
 
-  api.build.ninja(
-      checkout_root=checkout.root_dir,
-      gn_results=gn_results,
-  )
+  api.build.ninja(gn_results=gn_results)
 
   out_dir = api.path['start_dir'].join('docs_out')
   docs_dir = api.path['start_dir'].join('firebase')
diff --git a/recipes/fuchsia_cipd_roller.py b/recipes/fuchsia_cipd_roller.py
index 1de058b..f580aa7 100644
--- a/recipes/fuchsia_cipd_roller.py
+++ b/recipes/fuchsia_cipd_roller.py
@@ -249,7 +249,6 @@
         str(gn_results.fuchsia_build_dir),
     )
     api.build.ninja(
-        checkout_root=api.path['start_dir'],
         gn_results=gn_results,
         build_zircon=False,
         targets=[upload_debug_symbols_target],
diff --git a/recipes/zbi_test.py b/recipes/zbi_test.py
index 9604ba7..13d2e65 100644
--- a/recipes/zbi_test.py
+++ b/recipes/zbi_test.py
@@ -397,7 +397,6 @@
     )
 
     api.build.ninja(
-        checkout_root=checkout.root_dir,
         gn_results=gn_results,
         targets=['bundles:infratools'],
         build_zbi_tests=True,