use Pass::Run to set the context on each pass. (#1708)

Currently the IRContext is passed into the Pass::Process method. It is
then up to the individual pass to store the context into the context_
variable. This CL changes the Run method to store the context before
calling Process which no-longer receives the context as a parameter.
diff --git a/source/opt/inline_pass.cpp b/source/opt/inline_pass.cpp
index e37fc38..960baf6 100644
--- a/source/opt/inline_pass.cpp
+++ b/source/opt/inline_pass.cpp
@@ -668,9 +668,7 @@
          no_return_in_loop_.cend();
 }
 
-void InlinePass::InitializeInline(opt::IRContext* c) {
-  InitializeProcessing(c);
-
+void InlinePass::InitializeInline() {
   false_id_ = 0;
 
   // clear collections