Create `loadLibrary` function element eagerly.

pkg/analyzer/lib/src/context/context.dart

Index: pkg/analyzer/lib/src/context/context.dart
diff --git a/pkg/analyzer/lib/src/context/context.dart b/pkg/analyzer/lib/src/context/context.dart
index dd2893f8fedc004f8b5f916bade9924fdcaa814a..dcf988bb54e73ab9e59ce11e91bf29eeadad346d 100644
--- a/pkg/analyzer/lib/src/context/context.dart
+++ b/pkg/analyzer/lib/src/context/context.dart
@@ -631,6 +631,7 @@ class AnalysisContextImpl implements InternalAnalysisContext {
 
   @override
   LibraryElement computeLibraryElement(Source source) {
+    assert(!driver.isTaskRunning);

[Brian Wilkerson, 2015/10/19 20:15:19]

Do we want to add this, or was this left over from debugging?

If we want to add it, consider putting it in computeResult just before asking
the driver to do some work.

[Paul Berry, 2015/10/19 20:31:29]

This was added on purpose--in the absence of the bug fix, it changes the bug
from non-deterministic to deterministic by doing the reentrancy check prior to
checking whether the result has already been computed.  That should help us
catch the problem more quickly in the event of a regression.
Seems reasonable--that has the potential to catch more bugs.  I've moved it to
the top of computeResult, though (rather than just before asking the driver to
do some work) to preserve the determinism.

I've also added a comment to clarify what the check is for so that it doesn't
look like it was included by accident.

     //_computeResult(source, HtmlEntry.ELEMENT);
     return computeResult(source, LIBRARY_ELEMENT);
   }