camera_metadata: Update lens aperture related tags

Change-Id: I542630509a7bb867bcf780d5d5b4542c36dd74cf
diff --git a/camera/docs/docs.html b/camera/docs/docs.html
index 54ceda3..30eac35 100644
--- a/camera/docs/docs.html
+++ b/camera/docs/docs.html
@@ -6047,7 +6047,8 @@
             </td> <!-- entry_type -->
 
             <td class="entry_description">
-              <p>Size of the lens aperture</p>
+              <p>The ratio of lens focal length to the effective
+aperture diameter.<wbr/></p>
             </td>
 
             <td class="entry_units">
@@ -6070,8 +6071,20 @@
           </tr>
           <tr class="entry_cont">
             <td class="entry_details" colspan="5">
-              <p>Will not be supported on most devices.<wbr/> Can only
-pick from supported list</p>
+              <p>This will only be supported on the camera devices that
+have variable aperture lens.<wbr/> The aperture value can only be
+one of the values listed in <a href="#static_android.lens.info.availableApertures">android.<wbr/>lens.<wbr/>info.<wbr/>available<wbr/>Apertures</a>.<wbr/></p>
+<p>When this is supported and <a href="#controls_android.control.aeMode">android.<wbr/>control.<wbr/>ae<wbr/>Mode</a> is OFF,<wbr/>
+this can be set along with <a href="#controls_android.sensor.exposureTime">android.<wbr/>sensor.<wbr/>exposure<wbr/>Time</a>,<wbr/>
+<a href="#controls_android.sensor.sensitivity">android.<wbr/>sensor.<wbr/>sensitivity</a>,<wbr/> and android.<wbr/>sensor.<wbr/>frame<wbr/>Duration
+to achieve manual exposure control.<wbr/></p>
+<p>The requested aperture value may take several frames to reach the
+requested value; the camera device will report the current (intermediate)
+aperture size in capture result metadata while the aperture is changing.<wbr/></p>
+<p>When this is supported and <a href="#controls_android.control.aeMode">android.<wbr/>control.<wbr/>ae<wbr/>Mode</a> is one of
+the ON modes,<wbr/> this will be overridden by the camera device
+auto-exposure algorithm,<wbr/> the overridden values are then provided
+back to the user in the corresponding result.<wbr/></p>
             </td>
           </tr>
 
@@ -6321,14 +6334,14 @@
 
             <td class="entry_description">
               <p>List of supported aperture
-values</p>
+values.<wbr/></p>
             </td>
 
             <td class="entry_units">
             </td>
 
             <td class="entry_range">
-              <p>one entry required,<wbr/> &gt; 0</p>
+              <p>one entry required,<wbr/> &amp;&gt; 0</p>
             </td>
 
             <td class="entry_tags">
@@ -6343,8 +6356,10 @@
           </tr>
           <tr class="entry_cont">
             <td class="entry_details" colspan="5">
-              <p>If variable aperture not available,<wbr/> only setting
-should be for the fixed aperture</p>
+              <p>If the camera device doesn't support variable apertures,<wbr/>
+listed value will be the fixed aperture.<wbr/></p>
+<p>If the camera device supports variable apertures,<wbr/> the aperture value
+in this list will be sorted in ascending order.<wbr/></p>
             </td>
           </tr>
 
@@ -6923,7 +6938,8 @@
             </td> <!-- entry_type -->
 
             <td class="entry_description">
-              <p>Size of the lens aperture</p>
+              <p>The ratio of lens focal length to the effective
+aperture diameter.<wbr/></p>
             </td>
 
             <td class="entry_units">
@@ -6946,8 +6962,20 @@
           </tr>
           <tr class="entry_cont">
             <td class="entry_details" colspan="5">
-              <p>Will not be supported on most devices.<wbr/> Can only
-pick from supported list</p>
+              <p>This will only be supported on the camera devices that
+have variable aperture lens.<wbr/> The aperture value can only be
+one of the values listed in <a href="#static_android.lens.info.availableApertures">android.<wbr/>lens.<wbr/>info.<wbr/>available<wbr/>Apertures</a>.<wbr/></p>
+<p>When this is supported and <a href="#controls_android.control.aeMode">android.<wbr/>control.<wbr/>ae<wbr/>Mode</a> is OFF,<wbr/>
+this can be set along with <a href="#controls_android.sensor.exposureTime">android.<wbr/>sensor.<wbr/>exposure<wbr/>Time</a>,<wbr/>
+<a href="#controls_android.sensor.sensitivity">android.<wbr/>sensor.<wbr/>sensitivity</a>,<wbr/> and android.<wbr/>sensor.<wbr/>frame<wbr/>Duration
+to achieve manual exposure control.<wbr/></p>
+<p>The requested aperture value may take several frames to reach the
+requested value; the camera device will report the current (intermediate)
+aperture size in capture result metadata while the aperture is changing.<wbr/></p>
+<p>When this is supported and <a href="#controls_android.control.aeMode">android.<wbr/>control.<wbr/>ae<wbr/>Mode</a> is one of
+the ON modes,<wbr/> this will be overridden by the camera device
+auto-exposure algorithm,<wbr/> the overridden values are then provided
+back to the user in the corresponding result.<wbr/></p>
             </td>
           </tr>
 
diff --git a/camera/docs/metadata_properties.xml b/camera/docs/metadata_properties.xml
index a70f306..bd7cc2d 100644
--- a/camera/docs/metadata_properties.xml
+++ b/camera/docs/metadata_properties.xml
@@ -1355,11 +1355,27 @@
     <section name="lens">
       <controls>
         <entry name="aperture" type="float" visibility="public">
-          <description>Size of the lens aperture</description>
+          <description>The ratio of lens focal length to the effective
+          aperture diameter.</description>
           <units>f-number (f/NNN)</units>
           <range>android.lens.info.availableApertures</range>
-          <details>Will not be supported on most devices. Can only
-          pick from supported list</details>
+          <details>This will only be supported on the camera devices that
+          have variable aperture lens. The aperture value can only be
+          one of the values listed in android.lens.info.availableApertures.
+
+          When this is supported and android.control.aeMode is OFF,
+          this can be set along with android.sensor.exposureTime,
+          android.sensor.sensitivity, and android.sensor.frameDuration
+          to achieve manual exposure control.
+
+          The requested aperture value may take several frames to reach the
+          requested value; the camera device will report the current (intermediate)
+          aperture size in capture result metadata while the aperture is changing.
+
+          When this is supported and android.control.aeMode is one of
+          the ON modes, this will be overridden by the camera device
+          auto-exposure algorithm, the overridden values are then provided
+          back to the user in the corresponding result.</details>
           <tag id="V1" />
         </entry>
         <entry name="filterDensity" type="float" visibility="public">
@@ -1409,10 +1425,13 @@
               <size>n</size>
             </array>
             <description>List of supported aperture
-            values</description>
-            <range>one entry required, &amp;gt; 0</range>
-            <details>If variable aperture not available, only setting
-            should be for the fixed aperture</details>
+            values.</description>
+            <range>one entry required, &amp;&gt; 0</range>
+            <details>If the camera device doesn't support variable apertures,
+            listed value will be the fixed aperture.
+
+            If the camera device supports variable apertures, the aperture value
+            in this list will be sorted in ascending order.</details>
             <tag id="V1" />
           </entry>
           <entry name="availableFilterDensities" type="float" visibility="public"