Fix references to https://sites.google.com/site/skiadocs/.

Makefile

 # Makefile that wraps the Gyp and build steps for Unix and Mac (but not Windows)
 # Uses "ninja" to build the code.
 #
 # Some usage examples (tested on both Linux and Mac):
 #
 #   # Clean everything
 #   make clean
 #
 #   # Build and run tests (in Debug mode)
 #   make dm
 #   out/Debug/dm
 #
 #   # Build and run tests (in Release mode)
 #   make dm BUILDTYPE=Release
 #   out/Release/dm
 #
 #   # Build bench and SampleApp (both in Release mode), and then run them
 #   make SampleApp bench BUILDTYPE=Release
 #   out/Release/bench -repeat 2
 #   out/Release/SampleApp
 #
 #   # Build all targets (in Debug mode)
 #   make
 #
 # If you want more fine-grained control, you can run gyp and then build the
 # gyp-generated projects yourself.
 #
-# See https://sites.google.com/site/skiadocs/ for complete documentation.
+# See https://skia.org for complete documentation.
 
 SKIA_OUT ?= out
 BUILDTYPE ?= Debug
 CWD := $(shell pwd)
 
 # Soon we should be able to get rid of VALID_TARGETS, and just pass control
 # to the gyp-generated Makefile for *any* target name.
 # But that will be a bit complicated, so let's keep it for a future CL.
 # Tracked as https://code.google.com/p/skia/issues/detail?id=947 ('eliminate
 # need for VALID_TARGETS in toplevel Makefile')
@@ skipping 21 matching lines @@
 default: most
 
 # As noted in http://code.google.com/p/skia/issues/detail?id=330 , building
 # multiple targets in parallel was failing.  The special .NOTPARALLEL target
 # tells gnu make not to run targets within this Makefile in parallel.
 # Targets that ninja builds at this Makefile's behest should not be affected.
 .NOTPARALLEL:
 
 uname := $(shell uname)
 ifneq (,$(findstring CYGWIN, $(uname)))
-  $(error Cannot build using Make on Windows. See https://sites.google.com/site/skiadocs/user-documentation/quick-start-guides/windows)
+  $(error Cannot build using Make on Windows. See https://skia.org/user/quick/windows)
 endif
 
 # If user requests "make all", chain to our explicitly-declared "everything"
 # target. See https://code.google.com/p/skia/issues/detail?id=932 ("gyp
 # automatically creates "all" target on some build flavors but not others")
 .PHONY: all
 all: everything
 
 .PHONY: clean
 clean:
         rm -rf out xcodebuild
 ifneq (out, $(SKIA_OUT))
         rm -rf $(SKIA_OUT)
 endif
 
 # Run gyp no matter what.
 .PHONY: gyp
 gyp:
         $(CWD)/gyp_skia
 
 # For all specific targets: run gyp if necessary, and then pass control to
 # the gyp-generated buildfiles.
 .PHONY: $(VALID_TARGETS)
 $(VALID_TARGETS):: gyp
         ninja -C $(SKIA_OUT)/$(BUILDTYPE) $@