Skip toolchain downloads for a few android tools.

This is an attempt to avoid downloading the android toolchain when not required.
I went through all binaries listed in https://code.google.com/p/chromium/codesearch#chromium/build/scripts/slave/recipe_modules/skia/android_flavor.py except for android_ninja.

BUG=skia:5119
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1832883002

Review URL: https://codereview.chromium.org/1832883002
diff --git a/platform_tools/android/bin/adb_pull_if_needed b/platform_tools/android/bin/adb_pull_if_needed
index f4992b2..6a35902 100755
--- a/platform_tools/android/bin/adb_pull_if_needed
+++ b/platform_tools/android/bin/adb_pull_if_needed
@@ -3,6 +3,7 @@
 # Copy the contents of a directory from a device to the host.
 
 SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+SKIP_TOOLCHAIN_SETUP="true"
 source $SCRIPT_DIR/android_setup.sh
 source $SCRIPT_DIR/utils/setup_adb.sh
 
diff --git a/platform_tools/android/bin/adb_push_if_needed b/platform_tools/android/bin/adb_push_if_needed
index 96e093f..efe6bb8 100755
--- a/platform_tools/android/bin/adb_push_if_needed
+++ b/platform_tools/android/bin/adb_push_if_needed
@@ -3,6 +3,7 @@
 # Copy the contents of a directory from the host to a device.
 
 SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+SKIP_TOOLCHAIN_SETUP="true"
 source $SCRIPT_DIR/android_setup.sh
 source $SCRIPT_DIR/utils/setup_adb.sh
 
diff --git a/platform_tools/android/bin/adb_wait_for_device b/platform_tools/android/bin/adb_wait_for_device
index c25502e..6e92bf9 100755
--- a/platform_tools/android/bin/adb_wait_for_device
+++ b/platform_tools/android/bin/adb_wait_for_device
@@ -3,6 +3,7 @@
 # Wait for the device to be connected.
 
 SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+SKIP_TOOLCHAIN_SETUP="true"
 source $SCRIPT_DIR/android_setup.sh
 source $SCRIPT_DIR/utils/setup_adb.sh
 
diff --git a/platform_tools/android/bin/android_kill_skia b/platform_tools/android/bin/android_kill_skia
index 09866b7..3c4a757 100755
--- a/platform_tools/android/bin/android_kill_skia
+++ b/platform_tools/android/bin/android_kill_skia
@@ -4,6 +4,7 @@
 
 SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
 
+SKIP_TOOLCHAIN_SETUP="true"
 source $SCRIPT_DIR/android_setup.sh
 source $SCRIPT_DIR/utils/setup_adb.sh
 
@@ -14,4 +15,4 @@
 else
     echo "Could not automatically determine OS!"
     exit 1;
-fi
\ No newline at end of file
+fi
diff --git a/platform_tools/android/bin/android_run_skia b/platform_tools/android/bin/android_run_skia
index b58b53f..95d9fd9 100755
--- a/platform_tools/android/bin/android_run_skia
+++ b/platform_tools/android/bin/android_run_skia
@@ -4,6 +4,7 @@
 # output, and kills the app if interrupted.
 
 SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+SKIP_TOOLCHAIN_SETUP="true"
 source $SCRIPT_DIR/android_setup.sh
 source $SCRIPT_DIR/utils/setup_adb.sh
 
diff --git a/platform_tools/android/bin/android_setup.sh b/platform_tools/android/bin/android_setup.sh
index 4b7a60f..fd05a98 100755
--- a/platform_tools/android/bin/android_setup.sh
+++ b/platform_tools/android/bin/android_setup.sh
@@ -162,8 +162,10 @@
   verbose "The build is targeting the device: $TARGET_DEVICE"
   exportVar DEVICE_ID $TARGET_DEVICE
 
-  # setup the appropriate cross compiling toolchains
-  source $SCRIPT_DIR/utils/setup_toolchain.sh
+  if [ -z "$SKIP_TOOLCHAIN_SETUP" ]; then
+    # setup the appropriate cross compiling toolchains
+    source $SCRIPT_DIR/utils/setup_toolchain.sh
+  fi
 
   DEFINES="${DEFINES} android_toolchain=${TOOLCHAIN_TYPE}"
   DEFINES="${DEFINES} android_buildtype=${BUILDTYPE}"