Updated the documentation for caching policies.

components/policy/resources/policy_templates.json

 {
 # policy_templates.json - Metafile for policy templates
 #
 # The content of this file is evaluated as a Python expression.
 #
 # This file is used as input to generate the following policy templates:
 # ADM, ADMX+ADML, MCX/plist and html documentation.
 #
 # Policy templates are user interface definitions or documents about the
 # policies that can be used to configure Chrome. Each policy is a name-value
@@ skipping 948 matching lines @@
       'supported_on': ['chrome.*:17-'],
       'features': {
         'dynamic_refresh': False,
         'per_profile': False,
       },
       'example_value': 104857600,
       'id': 110,
       'caption': '''Set disk cache size in bytes''',
       'desc': '''Configures the cache size that <ph name="PRODUCT_NAME">$1<ex>Google Chrome</ex></ph> will use for storing cached files on the disk.
 
-      If you set this policy, <ph name="PRODUCT_NAME">$1<ex>Google Chrome</ex></ph> will use the provided cache size regardless whether the user has specified the '--disk-cache-size' flag or not.
+      If you set this policy, <ph name="PRODUCT_NAME">$1<ex>Google Chrome</ex></ph> will use the provided cache size regardless whether the user has specified the '--disk-cache-size' flag or not. The value specified in this policy is not a hard boundary but rather a suggestion to the caching system, any value below a few megabytes is too small and will be rounded up to a sane minimum.
 
       If the value of this policy is 0, the default cache size will be used but the user will not be able to change it.
 
       If this policy is not set the default size will be used and the user will be able to override it with the --disk-cache-size flag.''',
       'label': '''Set disk cache size''',
     },
     {
       'name': 'MediaCacheSize',
       'type': 'int',
       'schema': { 'type': 'integer' },
       'supported_on': ['chrome.*:17-'],
       'features': {
         'dynamic_refresh': False,
         'per_profile': False,
       },
       'example_value': 104857600,
       'id': 111,
       'caption': '''Set media disk cache size in bytes''',
       'desc': '''Configures the cache size that <ph name="PRODUCT_NAME">$1<ex>Google Chrome</ex></ph> will use for storing cached media files on the disk.
 
-      If you set this policy, <ph name="PRODUCT_NAME">$1<ex>Google Chrome</ex></ph> will use the provided cache size regardless whether the user has specified the '--media-cache-size' flag or not.
+      If you set this policy, <ph name="PRODUCT_NAME">$1<ex>Google Chrome</ex></ph> will use the provided cache size regardless whether the user has specified the '--media-cache-size' flag or not. The value specified in this policy is not a hard boundary but rather a suggestion to the caching system, any value below a few megabytes is too small and will be rounded up to a sane minimum.
 
       If the value of this policy is 0, the default cache size will be used but the user will not be able to change it.
 
       If this policy is not set the default size will be used and the user will be able to override it with the --media-cache-size flag.''',
       'label': '''Set media disk cache size''',
     },
     {
       'name': 'DownloadDirectory',
       'type': 'string',
       'schema': { 'type': 'string' },
@@ skipping 4885 matching lines @@
       'desc': '''Text appended in parentheses to the policy name to indicate that it has been deprecated''',
       'text': 'deprecated',
     },
     'doc_recommended': {
       'desc': '''Text appended in parentheses next to the policies top-level container to indicate that those policies are of the Recommended level''',
       'text': 'Default Settings (users can override)',
     },
   },
   'placeholders': [],
 }